Posted by Andrew Sparrow (12.35.165.68) on November 16, 2000 at 10:23:36:
In Reply to: Depression, 5HT, and seratonin. posted by Paco on August 20, 2000 at 11:23:33:
It think you should know first of all that the word is spelled "serotonin" and not seratonin". As to your question of what pain is at the cellular level, it is the transmission of the chemical substance P, a neurotransmitter. Basically, when it's transmitted in excess of normal levels you experience pain in whatever area the peripheral nerves have caused it to be released. Opiates work by binding to presynaptic opiod receptors, which inhibit the release of substance P, and you feel either less or no pain as a result. Serotonin can also act as a painkiller at certain receptors (I think 5ht1B) by inhibiting the production of substance P, I think. It may block certain gates through which substance P is transmitted, but I'm not sure. Migraines are caused by stimulation of the 5ht2C receptors, which stimulate the trigeminal nerves, the main facial sensory nerve and motor nerve for the jaw. The stimulation of these nerves causes plasma extravasation in the dura, which is thought to be a component of neurogenic inflammation and a cause of migraine.