Rock Hard Biochemistry Porn
NO is produced by vascular endothelial cells in response to signaling molecules, such as acetylcholine and bradykinin, which activate NO synthase. The release of acetylcholine triggers a sequence of events leading to a influx of Ca2+ into the endothelial cells. Ca2+ binds to calmodulin, which stimulates NO synthase. NO diffuses from the endothelial cell into neighboring smooth muscle cells where it binds to and activates a soluble guanylate cyclase. The guanylate cyclase converts GTP to cGMP in a manner analogous to the formation of cAMP from ATP by andenylate cyclase. A cGMP activates another serine/threonine protein kinase, referred to as cGMP-dependent protein kinase. The activity of cGMP-dependent protein kinase leads to smooth muscle relaxation and increased blood flow.
NO has a very short half-life in blood or other body fluids and is converted rapidly to nitrate or nitrite. cGMP is converted to GMP by phosphodiesterases; therefore, NO signaling is typically of short duration.
Unless, it's over four hours...then you have to see a physician...or take a picture.
Love
Jennie ;)
Sometimes, I love my biochem notes....
ETA: Here is my study guide answer to "How does Viagra work":
Viagra: it is a relatively-specific cGMP-phosphodiesterase inhibitor. Upon administration, cGMP levels remain elevated for longer following NO release and blood vessels remain relaxed. Blood flow is increased, leading to happier men and women.
NO has a very short half-life in blood or other body fluids and is converted rapidly to nitrate or nitrite. cGMP is converted to GMP by phosphodiesterases; therefore, NO signaling is typically of short duration.
Unless, it's over four hours...then you have to see a physician...or take a picture.
Love
Jennie ;)
Sometimes, I love my biochem notes....
ETA: Here is my study guide answer to "How does Viagra work":
Viagra: it is a relatively-specific cGMP-phosphodiesterase inhibitor. Upon administration, cGMP levels remain elevated for longer following NO release and blood vessels remain relaxed. Blood flow is increased, leading to happier men and women.