Because I'm a big ol' geek...
who's really interested in g-spot physiology; I'm pasting a this here mostly for my own future reference:
Beyond the G spot: Where do we go from here? World Congress of Sexology
Here is an edited version of the text of a speech Delivered in November, 1999, By Dr. Beverly Whipple, the president of the American Association of Sex Educators, Counselors, at the 1999 Joint Annual Meeting The Society for the Scientific Study of Sexuality and American Association of Sex Educators, Counselors, and Therapists.
Beverly Whipple, Ph.D., RN, FAAN
President AASECT, Author & Certified Counselor on Sexuality
I am honored to have the opportunity to discuss some of our interdisciplinary research concerning female sexual response and to talk about where do we go from here. I will be summarizing 20 years of research in the next hour, from vaginal orgasm to PET scans of the brain during orgasm.
Before I can discuss research findings, it is important to me to put these findings into a context of how I view sexuality and sexual expression. In the past, sexuality was viewed as having one purpose, and that purpose was reproduction. Today it is seen as an important aspect of health; it enhances the quality of life, fosters personal growth and contributes to human fulfillment. When the term sexuality is viewed holistically, it refers to the totality of a being.
It refers to human qualities, not just to the genitals and their functions. It includes all the qualities--biological, psychological, emotional, cultural, social and spiritual---that make people who they are. And people have the capacity to express their sexuality in any of these areas, it doesn't have to be just through the genitals.
It is important for....sexual health care providers, to consider what the person and/or the couple view as their goal of sexual expression. Whenever I discuss our research, I always present it in terms of "Timmers model." That is, I do not want to have people set up our findings as a goal that they or the individual or couple they are counseling must achieve. Our objective has been to validate women's sexual experiences, not create new goals.
According to Timmers et al. there are two commonly held views.
The most common view is goal-directed, which is analogous to climbing a flight of stairs. The first step is touch, the next step kissing, the next steps are caressing, then vagina/penis contact, which leads to intercourse and the top step of orgasm. There is a goal that both or one partner has in mind, and that goal is orgasm.
If the sexual experience does not lead to the achievement of that goal, then the couple or the person who is goal oriented does not feel good about all that has been experienced.
The alternative view is pleasure-directed, which can be conceptualized as a circle, with each expression on the perimeter of the circle considered an end in itself. Whether the experience is kissing, oral sex, holding, etc., each is an end in itself and each is satisfying to the couple. There is no need to have this form of expression lead to anything else.
If one person in a couple is goal-directed (and this is typically the male) and the other person is pleasure-directed (and this is typically the female, although it could be vice versa), problems may occur if they do not realize their goals or do not communicate their goals to their partner.
It was with the concept of pleasure-oriented sexual expression that John Perry and I listened to what women described as pleasurable to them. Listening to the reports of women who said they did not fit into the monolithic pattern of sexual response, that is, they had sexual pleasure, orgasm and in some cases an expulsion of fluid from vaginal stimulation, not clitoral stimulation, led to our rediscovery of a sexually sensitive area felt through the vaginal wall, which we called the Grafenberg or "G spot."
This sensitive area is usually located about halfway between the back of the pubic bone and the cervix, along the course of the urethra and near the neck of the bladder. It swells when it is stimulated, although it is difficult to palpate in an unstimulated stated. (published in Journal of Sex Research 1981 by Perry and Whipple and The G Spot 1982 by Ladas, Whipple and Perry)
The Grafenberg spot has not been found universally by all researchers who have conducted sexological examinations of the vagina. It may be that not all women have this distinct area, or the lack of universality may be due to the different methods of stimulating or different criteria for identifying this area.
In addition to vaginal sensitivity, some women reported that they had orgasm from vaginal stimulation. Masters and Johnson and Kaplan reported that there is only one reflex pathway in sexual response. In women, the clitoris is reported to be the major source of sensory input, the pudendal nerve is its sensory pathway, and the "orgasmic platform" undergoes myotonic buildup and discharge during orgasm.
Perry and I described a second reflex pathway that included the Grafenberg spot as the major source of stimulation, the pelvic nerve and the hypogastric plexus as its major pathway and the musculature of the uterus, the bladder, the urethra, the contractile elements associated with the paraurethral glands, and the proximal portion of the pubococcygeus muscle as its major myotonic responder. We claimed that this double-reflex concept could account for the reported ability of some women to selectively experience "vulva," "uterine" or "blended" orgasm, as described by Singer. (published in The G Spot, 1982)
Based on studies in laboratory rats, the pelvic nerve conveys afferent activity from the vagina and conveys efferent activity to the pubococcygeus muscle.This later study provides evidence that vaginal stimulation can produce pubococcygeus muscle contraction and indicates a possible reflex pathway (afferent and efferent) by which vaginal stimulation can produce an orgasmic response. (published in Physiology and Behavior, 1989)
I became interested in the phenomenon of female ejaculation, because I was teaching women to do kegel exercises using biofeedback for stress urinary incontinence. However, we found that some of our subjects were women who only lost fluid at orgasm and these women seemed to have very strong pubococcygeus muscles. So we designed a study to determine if there was a significant difference in the muscle strength of women who claimed to ejaculate.
We developed a device to measure uterine muscle strength in addition to PC muscle strength, because of our hypothesis that there are two nerves involved in sexual response.
The phenomenon of female ejaculation refers to expulsions of fluid from the urethra. Many women reported having surgery to correct this "problem" and others reported that they stopped having orgasm to prevent "wetting the bed." The fluid was described as looking like watered down skim milk, tasting sweet and usually about a teaspoon in volume.
Six studies have been published in which the fluid expelled from the urethra has been subjected to chemical analysis. In four of these studies, the ejaculated fluid was chemically significantly different from urine, while in two studies, no significant difference was observed. Others have reported an expulsion of fluid with and without chemical analysis. The data reported in this slide show a significant difference between urine and female ejaculate in terms of prostatic acid phosphatase, urea and creatinine.
We have also found a significant elevation in glucose in the ejaculate and other researchers report a significant elevation in fructose. (Most of these studies have been published in the Journal of Sex Research, ie Addiego et al 1981, Belzer et al, 1984, Zavicic et al, etc.) Cabello from Spain, reported at the last World Congress in Valencia that he tested the hypothesis that all women ejaculate, although some may have retrograde ejaculation. Using Microparticle Enzyme Immunoassay to detect prostate specific antigen (PSA), he found a significant difference in PSA between preorgasmic and postorgasmic urine specimens (published in the Proceedings of the World Congress of Sexology, 1997)
Based on these findings, it is evident that some women expel a fluid that is different from urine during sexual activities and orgasm and some women may expel a little urine. In some women G spot stimulation, orgasm and female ejaculation are related, while in other women they are not related.
Some women have reported experiencing ejaculation with orgasm from clitoral stimulation and some have reported experiencing ejaculation without orgasm. It is hoped that sexual health care providers can counsel women and their partners to feel more comfortable with the normal phenomenon of female ejaculation and therefore avoid surgery designed to eliminate it. This phenomenon is reported by most women who experience it as extremely pleasurable.
Is the G spot just for pleasure or does it have adaptive significance? An extensive series of studies in laboratory rats demonstrated that vaginal mechanical stimulation produced a strong pain blocking effect, stronger than 10 mg of morphine per kg of body weight. However, the most convincing evidence that vaginocervical stimulation blocks pain requires a verbal confirmation from women.
Consequently, we performed a series of studies in women, measuring pain thresholds during vaginal self-stimulation.
Pain thresholds were determined by applying a gradually increasing force to teach finger of one hand using a Ugo Basile Analgesia Meter. The subject places one finger on the 1 mm diameter point of the analgesia meter and a controlled, steadily increasing force is applied ranging from 0 grams to a maximum of 1 kg. The subject reports by saying "now," when the finger pain is first perceived (defined as "pain detection threshold") and by saying "stop," when finger pain becomes too uncomfortable to continue (defined as "pain tolerance threshold"). The pressure device is lifted from the finger when the subject says stop. Tactile thresholds are determined by applying a graded series of nylon monofilaments of varied stiffness (von Frey fibers) to the dorsal surface of the hand.
We found that the elevation in pain detection threshold increased by a mean of 47% when pressure was self-applied to the anterior vaginal wall (the Grafenberg spot). When stimulation was applied in a pleasurable manner, the pain threshold was greater (by 84%) than that in the resting control condition. The PD threshold increased by a mean of 107% when the women reported orgasm.
There were no increases in tactile (or touch) thresholds. This demonstrates that the effect was analgesic not an anesthetic effect and not a distracting effect. This analgesic effect was produced by pressure and by pleasurable self-stimulation applied to the anterior vaginal wall (G spot). (this was published in the journal Pain., 1985, by Whipple and Komisaruk)
Pleasurable self-stimulation, but not pressure applied to other genital regions also produced an analgesic effect. (Published in Journal of Sex Research., 1988, Whipple and Komisaruk) It was then demonstrated that an analgesic effect also occurs naturally during labor.
We believe that childbirth would be more painful without this natural pain blocking effect, which is activated when the pelvic and hypogastric nerves are stimulated as the cervix dilates and from pressure in the vagina produced by the emerging fetus. (Published in International Journal of Nursing Studies, 1990, Whipple et al)
Further animal studies revealed that when newborn rats are injected with the chemical capsaicin, they do not get this natural analgesia when they are adults.
This led to a very interesting study that was based on my observations made of women during labor. That is, Spanish speaking women in my country seemed to have a harder time at labor, which I thought was cultural, until I learned of the studies with laboratory rats. I hypothesized that women who have chronically ingested a diet high in chili peppers (the main pungent ingredient of which is capsaicin) would have a diminished analgesic response to vaginal self-stimulation.
We conducted this study in Mexico, where we found women who fell into 3 different groups, depending on their dietary consumption of chili peppers. The results of this study supported my hypothesis, that is women who had diets high in chili peppers did not have the elevation in pain thresholds that women in Mexico had who did not eat chili peppers.
The group of women who did not eat chili peppers had pain thresholds very similar to the women in the United States; that is they had the natural pain blocking effect. (This was published in Physiology and Behavior in 1989, Whipple et al, and still tops the list for my most frequently requested publication) We are currently conducting a study in Mexico, comparing pain thresholds of women during labor who have had a diet high in chili peppers with those who had a diet low in chili peppers. Anecdotal reports from other countries, such as India, state that women are told not to eat hot spicy food about 3 months before they are due to deliver.
Orgasm has been reported to occur in response to imagery in the absence of any physical stimulation. In another study, we (Whipple, Ogden and Komisaruk) documented orgasm from imagery alone in the laboratory.
We measured heart rate, blood pressure, pupil diameter, and pain and tactile thresholds in women who had orgasm from genital self-stimulation and orgasm from imagery alone. Orgasm from self-induced imagery or genital self-stimulation generated significant increases in systolic blood pressure, heart rate, pupil diameter and pain thresholds over resting control conditions.
In these women, there were no significant differences in the increases in the physiological and perceptual correlates of orgasm from genital self-stimulation and from imagery alone. Physical genital stimulation is evidently not necessary to produce a state that is reported to be an orgasm. (Published in Archives of Sexual Behavior., 1992, Whipple et al) We may have to re-look at our definition of orgasm and we may have to believe women when they say they have had an orgasm, even if no one, including the women themselves, has physically stimulated her body.
Sexuality in Women With Spinal Cord Injury
Orgasmic response in women with complete spinal cord injury
We are continuing our research program by validating the subjective reports of women with complete spinal cord injury (SCI), that they do indeed experience orgasm. These women have been told, based on the literature, that they could not experience orgasm, or if they did, it was "phantom orgasm."
Based on extensive studies in laboratory rats concerning the neural pathways and neurotransmitters involved in the pain blocking and other effects of vaginal mechanical stimulation, we have documented that women with complete spinal cord injury do indeed experience orgasm from self-stimulation of the anterior wall of the vagina, the cervix, and a hypersensitive area of their body.
We hypothesized that the hypogastric nerve could convey cervical stimulation-elicited activity to the brain in women with complete SCI below T-10, since the fibers of the hypogastric nerve enter the spinal cord at T-10 and below. Furthermore, we hypothesized that women with complete SCI above the level of entry of the hypogastric nerve would have no sexual response or analgesia to vaginal or cervical self-stimulation.
We measured responses to vaginal and cervical self-stimulation in women with a confirmed diagnosis of complete SCI. The lower SCI groups had a complete SCI above the level of entry of the pelvic nerves but not the hypogastric nervesand the Upper SCI groups had complete SCI above the level of entry of both the pelvic and hypogastric nerves.
The third group, control, was composed of women without SCI. A tampon stimulator was designed and used for vaginal self-stimulation and another for cervical self-stimulation. There is a pressure transducer embedded in the holder behind the aluminum head so that we can monitor the amount of pressure the subject is self-applying. .... the stimulator is directed to the area of the Grafenberg spot.
The tampon is attached to a diaphragm for cervical self-stimulation. Orgasm was observed and reported in three of the 16 women with SCI and one of the 5 women without SCI.
During vaginal self-stimulation and cervical self-stimulation the control group and the lower level SCI group showed significant increases in BP over the corresponding resting control conditions.
During vaginal self-stimulation and cervical self-stimulation the control group showed significant increases in HR over the resting control condition. BP and HR in response to vaginal and cervical self-stimulation appear to be mediated by different mechanisms, since BP in women with SCI (lower level) increased during vaginal and cervical self-stimulation, whereas HR did not change significantly in either SCI group. (Published in Journal of Sex Research., 1996, Whipple, Gerdes, Komisaruk)
In the control group, vaginal self-stimulation significantly increased the pain detection threshold by 67%. In support of our hypothesis that genital self-simulation would increase pain thresholds in women with complete SCI below the level of entry of the hypogastric nerve, vaginal self-stimulation significantly increased PD threshold by 35%. Unexpectedly, and a major finding, vaginal self-stimulation significantly increased PD threshold by 92% in the upper SCI group, without any known genital input.
In addition, cervical self-stimulation significantly increased PD in the uninjured group by 55%, and by 34% in the lower SCI group, and by 73% in the upper SCI group. The increase in PD threshold produced by vaginal or cervical self-stimulation in the groups with upper SCI was significantly greater than that in the groups with lower SCI. By contrast, neither vaginal nor cervical self-stimulation significantly increased tactile thresholds in these groups. (Published in Archives of Neurology, 1997, Komisaruk, Gerdes, and Whipple)These women reported that they did not use imagery during this laboratory study.
We then postulated the existence of a sensory pathway that bypasses the spinal cord, carrying sensory input from the vagina and cervix directly to the brain. We hypothesized that this pathway is the vagus nerve.
In the laboratory rat, after injection of the tracer, horseradish peroxidase, into the wall of the cervix and uterus, the tracer was found in cell bodies of the nodose ganglion, which is the sensory ganglion of the vagus nerve. To further test this hypothesis, we transected either the spinal cord or all nerves known to respond to genital stimulation (pelvic, hypogastric and pudendal) in the laboratory rat and tested for responses to vaginocervical stimulation. These transections reduced the magnitude of brain-mediated responses, leaving a significant residual response. Bilateral transection of the vagus nerves at the subdiaphragmatic level abolished these residual responses.
To test whether the vagus nerve can convey afferent activity from the cervix to the brain in women with and without spinal cord injury, we are conducting PET scans of the brain to ascertain if cervical self-stimulation activates the region of the Nucleus of the Solitary tract (NTS), which receives the primary afferent terminals of the vagus nerve.
Using the method of PET scan, coupled with MRI to provide neuroanatomical localization, we ascertained whether cervical self-stimulation activates the region of the nucleus of the solitary tract, as our measure of whether genital sensory input can gain access to the brain via the vagus nerves in women with complete spinal cord injury.
In a pilot study with two women with complete SCI above T-10 and one woman without SCI, we have observed evidence of activation of the region of the NTS in response to cervical self-stimulation. We have also demonstrated that in the two women with SCI there was no activation of the somatosensory thalamus in response to foot stimulation, although the uninjured control subject showed a strong response. This indicates that the ascending pathways through the spinal cord were indeed interrupted in these two women with complete SCI.
By contrast, all women showed responses in the NTS, the nucleus of the solitary tract. This indicates that despite the blockage in the spinal cord, the vagus nerve was still able to convey the cervical sensory input directly to the brain. Thus, these preliminary findings support our hypothesis that the vagus nerve can carry genital sensory information to the brain even if the major spinal cord pathways are interrupted.
It is important to note, based on pilot data, that the sensory vagus nerve may be involved in sexual response in women with or without neurological impairment.
Based on these studies, we can conclude that vaginal and cervical stimulation clearly exert powerful perceptual and physiological effects. It may be possible to harness these responses for therapeutic benefit, for example in the control of pain and in the augmentation of sexual response. Further research on this pathway could lead to methods of amplifying activity in this pathway by pharmacological means and/or by biofeedback, which could lead to improved prognosis for rehabilitation and quality of life in women with complete SCI at any level.
We are now extending the PET scan studies to map the brain regions that mediate the responses to vaginal-cervical stimulation beyond the first synapse, in the case of pain blockage and sexual response, including orgasm. We anticipate that these studies will provide insight as to where in the brain pain is blocked and orgasm is generated.
I do not have time to go into our extensive research concerning vasoactive intestinal peptide, which is released into the spinal cord in response to vaginal stimulation in laboratory rats, and which produces a stronger analgesic effect than morphine. VIP is a vasodilator that seems to be involved in sexual response in women in terms of pelvic vasculature and the pelvic nerve. Nitric Oxide may be involved in clitoral response (much more research is needed in this area.
I am very interested in the results of the clinical trials that Pfizer is conducting in women with Viagra. As you know Viagra affects arousal (lubrication) not lack of desire, or anorgasmia, which are the most common complaints of women.
In addition, when studies have been conducted concerning lubrication in women, many women have perfuse lubrication and report that they are not aroused. So giving a drug to induce lubrication may not be meeting the needs of women. I find it interesting that urologists are asking me to speak about female sexual response.
The American Urology Foundation also sponsored 19 of us from around the world to be part of a consensus conference concerning female sexual dysfunction. I am glad that others are now interested in female sexual response, but I hope it is not just to give a pill, but to help women to learn more about themselves and to be more accepting of their sexual responses.
The Future
Lets look for a few minutes at where we will be going with sexuality research in the future. First of all, I believe that we have to stop extrapolating research finding in men and applying them to women. There may be some similarities, but there are many differences as well. Women have to be the focus of specific studies.
We have to conduct more international studies and look at cross cultural similarities and differences. Laboratory research is very weak in its ability to understand how sociocultural and partner variables affect sexual response.
In the future we will be conducting more research using newer technologies, such as in home transducers (although the Foxes used them back in the 1970s), to take some of the research out of basic physiology laboratories. We will continue to use state of the art methodology such as PET scans and MRI's. And we will be making more use of the internet for qualitative research.
We have to determine if the basic physiological research we are conducting in our laboratories has meaning for sexual behavior under other conditions, such as with one's sexual partner.
And we have to continue to be open to hearing what women say brings them sexual pleasure and then continue to validate their experiences, and not try to fit them into a monolithic model of only one way to respond sexually and only one way to have sexual pleasure.
Whatever the final outcome in terms of neural pathways and neurotransmitters involved in sexual response, it is important for you to be aware of the variety of sexual responses that women report and that have been documented in the laboratory. It is also important that women be aware of what is pleasurable to them, acknowledge this to themselves and then communicate what they find pleasurable to their partners.
People need to be encouraged to feel good about the variety of ways they may achieve sexual pleasure, without setting up specific goals, such as finding the G spot or experiencing female ejaculation. Healthy sexuality begins with acceptance of the self, in addition to an emphasis on the process, rather than only the goals, of sexual interactions.
Beyond the G spot: Where do we go from here? World Congress of Sexology
Here is an edited version of the text of a speech Delivered in November, 1999, By Dr. Beverly Whipple, the president of the American Association of Sex Educators, Counselors, at the 1999 Joint Annual Meeting The Society for the Scientific Study of Sexuality and American Association of Sex Educators, Counselors, and Therapists.
Beverly Whipple, Ph.D., RN, FAAN
President AASECT, Author & Certified Counselor on Sexuality
I am honored to have the opportunity to discuss some of our interdisciplinary research concerning female sexual response and to talk about where do we go from here. I will be summarizing 20 years of research in the next hour, from vaginal orgasm to PET scans of the brain during orgasm.
Before I can discuss research findings, it is important to me to put these findings into a context of how I view sexuality and sexual expression. In the past, sexuality was viewed as having one purpose, and that purpose was reproduction. Today it is seen as an important aspect of health; it enhances the quality of life, fosters personal growth and contributes to human fulfillment. When the term sexuality is viewed holistically, it refers to the totality of a being.
It refers to human qualities, not just to the genitals and their functions. It includes all the qualities--biological, psychological, emotional, cultural, social and spiritual---that make people who they are. And people have the capacity to express their sexuality in any of these areas, it doesn't have to be just through the genitals.
It is important for....sexual health care providers, to consider what the person and/or the couple view as their goal of sexual expression. Whenever I discuss our research, I always present it in terms of "Timmers model." That is, I do not want to have people set up our findings as a goal that they or the individual or couple they are counseling must achieve. Our objective has been to validate women's sexual experiences, not create new goals.
According to Timmers et al. there are two commonly held views.
The most common view is goal-directed, which is analogous to climbing a flight of stairs. The first step is touch, the next step kissing, the next steps are caressing, then vagina/penis contact, which leads to intercourse and the top step of orgasm. There is a goal that both or one partner has in mind, and that goal is orgasm.
If the sexual experience does not lead to the achievement of that goal, then the couple or the person who is goal oriented does not feel good about all that has been experienced.
The alternative view is pleasure-directed, which can be conceptualized as a circle, with each expression on the perimeter of the circle considered an end in itself. Whether the experience is kissing, oral sex, holding, etc., each is an end in itself and each is satisfying to the couple. There is no need to have this form of expression lead to anything else.
If one person in a couple is goal-directed (and this is typically the male) and the other person is pleasure-directed (and this is typically the female, although it could be vice versa), problems may occur if they do not realize their goals or do not communicate their goals to their partner.
It was with the concept of pleasure-oriented sexual expression that John Perry and I listened to what women described as pleasurable to them. Listening to the reports of women who said they did not fit into the monolithic pattern of sexual response, that is, they had sexual pleasure, orgasm and in some cases an expulsion of fluid from vaginal stimulation, not clitoral stimulation, led to our rediscovery of a sexually sensitive area felt through the vaginal wall, which we called the Grafenberg or "G spot."
This sensitive area is usually located about halfway between the back of the pubic bone and the cervix, along the course of the urethra and near the neck of the bladder. It swells when it is stimulated, although it is difficult to palpate in an unstimulated stated. (published in Journal of Sex Research 1981 by Perry and Whipple and The G Spot 1982 by Ladas, Whipple and Perry)
The Grafenberg spot has not been found universally by all researchers who have conducted sexological examinations of the vagina. It may be that not all women have this distinct area, or the lack of universality may be due to the different methods of stimulating or different criteria for identifying this area.
In addition to vaginal sensitivity, some women reported that they had orgasm from vaginal stimulation. Masters and Johnson and Kaplan reported that there is only one reflex pathway in sexual response. In women, the clitoris is reported to be the major source of sensory input, the pudendal nerve is its sensory pathway, and the "orgasmic platform" undergoes myotonic buildup and discharge during orgasm.
Perry and I described a second reflex pathway that included the Grafenberg spot as the major source of stimulation, the pelvic nerve and the hypogastric plexus as its major pathway and the musculature of the uterus, the bladder, the urethra, the contractile elements associated with the paraurethral glands, and the proximal portion of the pubococcygeus muscle as its major myotonic responder. We claimed that this double-reflex concept could account for the reported ability of some women to selectively experience "vulva," "uterine" or "blended" orgasm, as described by Singer. (published in The G Spot, 1982)
Based on studies in laboratory rats, the pelvic nerve conveys afferent activity from the vagina and conveys efferent activity to the pubococcygeus muscle.This later study provides evidence that vaginal stimulation can produce pubococcygeus muscle contraction and indicates a possible reflex pathway (afferent and efferent) by which vaginal stimulation can produce an orgasmic response. (published in Physiology and Behavior, 1989)
I became interested in the phenomenon of female ejaculation, because I was teaching women to do kegel exercises using biofeedback for stress urinary incontinence. However, we found that some of our subjects were women who only lost fluid at orgasm and these women seemed to have very strong pubococcygeus muscles. So we designed a study to determine if there was a significant difference in the muscle strength of women who claimed to ejaculate.
We developed a device to measure uterine muscle strength in addition to PC muscle strength, because of our hypothesis that there are two nerves involved in sexual response.
The phenomenon of female ejaculation refers to expulsions of fluid from the urethra. Many women reported having surgery to correct this "problem" and others reported that they stopped having orgasm to prevent "wetting the bed." The fluid was described as looking like watered down skim milk, tasting sweet and usually about a teaspoon in volume.
Six studies have been published in which the fluid expelled from the urethra has been subjected to chemical analysis. In four of these studies, the ejaculated fluid was chemically significantly different from urine, while in two studies, no significant difference was observed. Others have reported an expulsion of fluid with and without chemical analysis. The data reported in this slide show a significant difference between urine and female ejaculate in terms of prostatic acid phosphatase, urea and creatinine.
We have also found a significant elevation in glucose in the ejaculate and other researchers report a significant elevation in fructose. (Most of these studies have been published in the Journal of Sex Research, ie Addiego et al 1981, Belzer et al, 1984, Zavicic et al, etc.) Cabello from Spain, reported at the last World Congress in Valencia that he tested the hypothesis that all women ejaculate, although some may have retrograde ejaculation. Using Microparticle Enzyme Immunoassay to detect prostate specific antigen (PSA), he found a significant difference in PSA between preorgasmic and postorgasmic urine specimens (published in the Proceedings of the World Congress of Sexology, 1997)
Based on these findings, it is evident that some women expel a fluid that is different from urine during sexual activities and orgasm and some women may expel a little urine. In some women G spot stimulation, orgasm and female ejaculation are related, while in other women they are not related.
Some women have reported experiencing ejaculation with orgasm from clitoral stimulation and some have reported experiencing ejaculation without orgasm. It is hoped that sexual health care providers can counsel women and their partners to feel more comfortable with the normal phenomenon of female ejaculation and therefore avoid surgery designed to eliminate it. This phenomenon is reported by most women who experience it as extremely pleasurable.
Is the G spot just for pleasure or does it have adaptive significance? An extensive series of studies in laboratory rats demonstrated that vaginal mechanical stimulation produced a strong pain blocking effect, stronger than 10 mg of morphine per kg of body weight. However, the most convincing evidence that vaginocervical stimulation blocks pain requires a verbal confirmation from women.
Consequently, we performed a series of studies in women, measuring pain thresholds during vaginal self-stimulation.
Pain thresholds were determined by applying a gradually increasing force to teach finger of one hand using a Ugo Basile Analgesia Meter. The subject places one finger on the 1 mm diameter point of the analgesia meter and a controlled, steadily increasing force is applied ranging from 0 grams to a maximum of 1 kg. The subject reports by saying "now," when the finger pain is first perceived (defined as "pain detection threshold") and by saying "stop," when finger pain becomes too uncomfortable to continue (defined as "pain tolerance threshold"). The pressure device is lifted from the finger when the subject says stop. Tactile thresholds are determined by applying a graded series of nylon monofilaments of varied stiffness (von Frey fibers) to the dorsal surface of the hand.
We found that the elevation in pain detection threshold increased by a mean of 47% when pressure was self-applied to the anterior vaginal wall (the Grafenberg spot). When stimulation was applied in a pleasurable manner, the pain threshold was greater (by 84%) than that in the resting control condition. The PD threshold increased by a mean of 107% when the women reported orgasm.
There were no increases in tactile (or touch) thresholds. This demonstrates that the effect was analgesic not an anesthetic effect and not a distracting effect. This analgesic effect was produced by pressure and by pleasurable self-stimulation applied to the anterior vaginal wall (G spot). (this was published in the journal Pain., 1985, by Whipple and Komisaruk)
Pleasurable self-stimulation, but not pressure applied to other genital regions also produced an analgesic effect. (Published in Journal of Sex Research., 1988, Whipple and Komisaruk) It was then demonstrated that an analgesic effect also occurs naturally during labor.
We believe that childbirth would be more painful without this natural pain blocking effect, which is activated when the pelvic and hypogastric nerves are stimulated as the cervix dilates and from pressure in the vagina produced by the emerging fetus. (Published in International Journal of Nursing Studies, 1990, Whipple et al)
Further animal studies revealed that when newborn rats are injected with the chemical capsaicin, they do not get this natural analgesia when they are adults.
This led to a very interesting study that was based on my observations made of women during labor. That is, Spanish speaking women in my country seemed to have a harder time at labor, which I thought was cultural, until I learned of the studies with laboratory rats. I hypothesized that women who have chronically ingested a diet high in chili peppers (the main pungent ingredient of which is capsaicin) would have a diminished analgesic response to vaginal self-stimulation.
We conducted this study in Mexico, where we found women who fell into 3 different groups, depending on their dietary consumption of chili peppers. The results of this study supported my hypothesis, that is women who had diets high in chili peppers did not have the elevation in pain thresholds that women in Mexico had who did not eat chili peppers.
The group of women who did not eat chili peppers had pain thresholds very similar to the women in the United States; that is they had the natural pain blocking effect. (This was published in Physiology and Behavior in 1989, Whipple et al, and still tops the list for my most frequently requested publication) We are currently conducting a study in Mexico, comparing pain thresholds of women during labor who have had a diet high in chili peppers with those who had a diet low in chili peppers. Anecdotal reports from other countries, such as India, state that women are told not to eat hot spicy food about 3 months before they are due to deliver.
Orgasm has been reported to occur in response to imagery in the absence of any physical stimulation. In another study, we (Whipple, Ogden and Komisaruk) documented orgasm from imagery alone in the laboratory.
We measured heart rate, blood pressure, pupil diameter, and pain and tactile thresholds in women who had orgasm from genital self-stimulation and orgasm from imagery alone. Orgasm from self-induced imagery or genital self-stimulation generated significant increases in systolic blood pressure, heart rate, pupil diameter and pain thresholds over resting control conditions.
In these women, there were no significant differences in the increases in the physiological and perceptual correlates of orgasm from genital self-stimulation and from imagery alone. Physical genital stimulation is evidently not necessary to produce a state that is reported to be an orgasm. (Published in Archives of Sexual Behavior., 1992, Whipple et al) We may have to re-look at our definition of orgasm and we may have to believe women when they say they have had an orgasm, even if no one, including the women themselves, has physically stimulated her body.
Sexuality in Women With Spinal Cord Injury
Orgasmic response in women with complete spinal cord injury
We are continuing our research program by validating the subjective reports of women with complete spinal cord injury (SCI), that they do indeed experience orgasm. These women have been told, based on the literature, that they could not experience orgasm, or if they did, it was "phantom orgasm."
Based on extensive studies in laboratory rats concerning the neural pathways and neurotransmitters involved in the pain blocking and other effects of vaginal mechanical stimulation, we have documented that women with complete spinal cord injury do indeed experience orgasm from self-stimulation of the anterior wall of the vagina, the cervix, and a hypersensitive area of their body.
We hypothesized that the hypogastric nerve could convey cervical stimulation-elicited activity to the brain in women with complete SCI below T-10, since the fibers of the hypogastric nerve enter the spinal cord at T-10 and below. Furthermore, we hypothesized that women with complete SCI above the level of entry of the hypogastric nerve would have no sexual response or analgesia to vaginal or cervical self-stimulation.
We measured responses to vaginal and cervical self-stimulation in women with a confirmed diagnosis of complete SCI. The lower SCI groups had a complete SCI above the level of entry of the pelvic nerves but not the hypogastric nervesand the Upper SCI groups had complete SCI above the level of entry of both the pelvic and hypogastric nerves.
The third group, control, was composed of women without SCI. A tampon stimulator was designed and used for vaginal self-stimulation and another for cervical self-stimulation. There is a pressure transducer embedded in the holder behind the aluminum head so that we can monitor the amount of pressure the subject is self-applying. .... the stimulator is directed to the area of the Grafenberg spot.
The tampon is attached to a diaphragm for cervical self-stimulation. Orgasm was observed and reported in three of the 16 women with SCI and one of the 5 women without SCI.
During vaginal self-stimulation and cervical self-stimulation the control group and the lower level SCI group showed significant increases in BP over the corresponding resting control conditions.
During vaginal self-stimulation and cervical self-stimulation the control group showed significant increases in HR over the resting control condition. BP and HR in response to vaginal and cervical self-stimulation appear to be mediated by different mechanisms, since BP in women with SCI (lower level) increased during vaginal and cervical self-stimulation, whereas HR did not change significantly in either SCI group. (Published in Journal of Sex Research., 1996, Whipple, Gerdes, Komisaruk)
In the control group, vaginal self-stimulation significantly increased the pain detection threshold by 67%. In support of our hypothesis that genital self-simulation would increase pain thresholds in women with complete SCI below the level of entry of the hypogastric nerve, vaginal self-stimulation significantly increased PD threshold by 35%. Unexpectedly, and a major finding, vaginal self-stimulation significantly increased PD threshold by 92% in the upper SCI group, without any known genital input.
In addition, cervical self-stimulation significantly increased PD in the uninjured group by 55%, and by 34% in the lower SCI group, and by 73% in the upper SCI group. The increase in PD threshold produced by vaginal or cervical self-stimulation in the groups with upper SCI was significantly greater than that in the groups with lower SCI. By contrast, neither vaginal nor cervical self-stimulation significantly increased tactile thresholds in these groups. (Published in Archives of Neurology, 1997, Komisaruk, Gerdes, and Whipple)These women reported that they did not use imagery during this laboratory study.
We then postulated the existence of a sensory pathway that bypasses the spinal cord, carrying sensory input from the vagina and cervix directly to the brain. We hypothesized that this pathway is the vagus nerve.
In the laboratory rat, after injection of the tracer, horseradish peroxidase, into the wall of the cervix and uterus, the tracer was found in cell bodies of the nodose ganglion, which is the sensory ganglion of the vagus nerve. To further test this hypothesis, we transected either the spinal cord or all nerves known to respond to genital stimulation (pelvic, hypogastric and pudendal) in the laboratory rat and tested for responses to vaginocervical stimulation. These transections reduced the magnitude of brain-mediated responses, leaving a significant residual response. Bilateral transection of the vagus nerves at the subdiaphragmatic level abolished these residual responses.
To test whether the vagus nerve can convey afferent activity from the cervix to the brain in women with and without spinal cord injury, we are conducting PET scans of the brain to ascertain if cervical self-stimulation activates the region of the Nucleus of the Solitary tract (NTS), which receives the primary afferent terminals of the vagus nerve.
Using the method of PET scan, coupled with MRI to provide neuroanatomical localization, we ascertained whether cervical self-stimulation activates the region of the nucleus of the solitary tract, as our measure of whether genital sensory input can gain access to the brain via the vagus nerves in women with complete spinal cord injury.
In a pilot study with two women with complete SCI above T-10 and one woman without SCI, we have observed evidence of activation of the region of the NTS in response to cervical self-stimulation. We have also demonstrated that in the two women with SCI there was no activation of the somatosensory thalamus in response to foot stimulation, although the uninjured control subject showed a strong response. This indicates that the ascending pathways through the spinal cord were indeed interrupted in these two women with complete SCI.
By contrast, all women showed responses in the NTS, the nucleus of the solitary tract. This indicates that despite the blockage in the spinal cord, the vagus nerve was still able to convey the cervical sensory input directly to the brain. Thus, these preliminary findings support our hypothesis that the vagus nerve can carry genital sensory information to the brain even if the major spinal cord pathways are interrupted.
It is important to note, based on pilot data, that the sensory vagus nerve may be involved in sexual response in women with or without neurological impairment.
Based on these studies, we can conclude that vaginal and cervical stimulation clearly exert powerful perceptual and physiological effects. It may be possible to harness these responses for therapeutic benefit, for example in the control of pain and in the augmentation of sexual response. Further research on this pathway could lead to methods of amplifying activity in this pathway by pharmacological means and/or by biofeedback, which could lead to improved prognosis for rehabilitation and quality of life in women with complete SCI at any level.
We are now extending the PET scan studies to map the brain regions that mediate the responses to vaginal-cervical stimulation beyond the first synapse, in the case of pain blockage and sexual response, including orgasm. We anticipate that these studies will provide insight as to where in the brain pain is blocked and orgasm is generated.
I do not have time to go into our extensive research concerning vasoactive intestinal peptide, which is released into the spinal cord in response to vaginal stimulation in laboratory rats, and which produces a stronger analgesic effect than morphine. VIP is a vasodilator that seems to be involved in sexual response in women in terms of pelvic vasculature and the pelvic nerve. Nitric Oxide may be involved in clitoral response (much more research is needed in this area.
I am very interested in the results of the clinical trials that Pfizer is conducting in women with Viagra. As you know Viagra affects arousal (lubrication) not lack of desire, or anorgasmia, which are the most common complaints of women.
In addition, when studies have been conducted concerning lubrication in women, many women have perfuse lubrication and report that they are not aroused. So giving a drug to induce lubrication may not be meeting the needs of women. I find it interesting that urologists are asking me to speak about female sexual response.
The American Urology Foundation also sponsored 19 of us from around the world to be part of a consensus conference concerning female sexual dysfunction. I am glad that others are now interested in female sexual response, but I hope it is not just to give a pill, but to help women to learn more about themselves and to be more accepting of their sexual responses.
The Future
Lets look for a few minutes at where we will be going with sexuality research in the future. First of all, I believe that we have to stop extrapolating research finding in men and applying them to women. There may be some similarities, but there are many differences as well. Women have to be the focus of specific studies.
We have to conduct more international studies and look at cross cultural similarities and differences. Laboratory research is very weak in its ability to understand how sociocultural and partner variables affect sexual response.
In the future we will be conducting more research using newer technologies, such as in home transducers (although the Foxes used them back in the 1970s), to take some of the research out of basic physiology laboratories. We will continue to use state of the art methodology such as PET scans and MRI's. And we will be making more use of the internet for qualitative research.
We have to determine if the basic physiological research we are conducting in our laboratories has meaning for sexual behavior under other conditions, such as with one's sexual partner.
And we have to continue to be open to hearing what women say brings them sexual pleasure and then continue to validate their experiences, and not try to fit them into a monolithic model of only one way to respond sexually and only one way to have sexual pleasure.
Whatever the final outcome in terms of neural pathways and neurotransmitters involved in sexual response, it is important for you to be aware of the variety of sexual responses that women report and that have been documented in the laboratory. It is also important that women be aware of what is pleasurable to them, acknowledge this to themselves and then communicate what they find pleasurable to their partners.
People need to be encouraged to feel good about the variety of ways they may achieve sexual pleasure, without setting up specific goals, such as finding the G spot or experiencing female ejaculation. Healthy sexuality begins with acceptance of the self, in addition to an emphasis on the process, rather than only the goals, of sexual interactions.