Effects of fenfluramine combined with electroacupuncture on monoamine release in periaqueductal gray of rat brain.

AIM To study the changes of monoamines in ventrolatoral periaqueductal gray of rat brain before and after electroacupuncture (EA) analgesia (EAA) was enhanced by fenfluramine (Fen), a 5-hydroxytryptamine (5-HT) releaser. METHODS Monoamines were collected by in vivo microdialysis and measured by HPLC connected with electrochemical detector. RESULTS The level of norepinephrine (Nor) after EA was decreased (P < 0.05 vs NS group). The contents of 5-HT, 5-hydroxyindol acetic acid (5-HIAA), dopamine (DA), and homovanillic acid (HVA) in periaqueductal gray dialysate were increased (P < 0.05 vs NS group). When Fen was combined with EA, the level of 5-HT and 5-HIAA were further increased (P < 0.05 vs NS + EA group). There was no obvious change of Nor, DA, and HVA. CONCLUSION Fen potentiating EAA may be related to further activation of serotoninergic system.