5-Ht: The Story So Far

Abstract

Serotonin (5-HT) has recently aroused great interest and has been linked to a number of therapeutic actions of acupuncture. It was originally discovered about 45 years ago to have a vasoconstrictor effect in the clotting mechanism, but is now known to be involved in numerous body processes including the modulation of a number of anterior pituitary hormones. Multiple 5-HT receptors have been identified and drugs with specific receptor action are being developed. Sumatripan is a 5-HT1 stimulator which has a vasoconstrictive effect, relieving migraine headaches. Ondansetron is a blocker of 5-HT3 receptors in the gut, thus being a very effective antiemetic in oncology treatment. Fluoxetine prevents 5-HT reuptake and thus has an antidepressant effect. As well as being endorphin mediated, the analgesic action of acupuncture has been shown to rely partly on 5-HT release: notably from nerves electrically stimulated at 200Hz. Acupuncture is a potent antiemetic, possibly acting by the same mechanism as ondansetron. It also has antidepressant action, perhaps through altering 5-HT mobilisation in the brain. Even the treatment of drug withdrawal symptoms by electroacupuncture may be by restabilising 5-HT at a normal level.