The role of central 5-hydroxytryptamine in acupuncture analgesia.

The role played by central 5-hydroxytryptamine (5-HT) in acupuncture analgesia (AA) has been studied in rats with the tail-flick response as the antinociceptive test. The analgesic effect of acupuncture can be enhanced or lowered by the increment or the decrement of the 5-HT level in the CNS. Furthermore, the turnover rate of 5-HT in the CNS has been found to be greatly facilitated during the period of acupuncture. The results imply that 5-HT in the CNS may be one of the most important neurochemical agents mediating AA.