Decrease of anesthetics activity by electroacupuncture on Jen-Chung point in rabbits

The effect of acupuncture at life-saving point on the central nervous depressive action of anesthetics was investigated in rabbits. Stimulation with electroacupuncture (EA) inserted in Jen-Chung point, which is located at the mid-point on the upper lip, decreased the sleeping time induced by pentobarbital or propofol. However, this action of acupuncture was not modified by naloxone at the doses sufficient to block opiate receptors. Plasma beta-endorphin detected by radioimmunoassay was also not markedly changed in rabbits which received similar electrostimulation. Moreover, pretreatment with para-chlorophenylalanine at a dose sufficient to deplete endogenous 5-hydroxytryptamine (5-HT) failed to influence the action of EA. Mediation of endogenous opioids and/or 5-HT in this action of EA was then ruled out. Prazosin reversed the sleeping time decreasing action of acupuncture in a dose-dependent manner. Also, the action of acupuncture was eliminated in rabbits which received intracerebroventricular injection of guanethidine at a dose which could block noradrenergic nerve terminals. It is suggested that stimulation of Jen-Chung point through EA can activate noradrenergic neurotransmission in the brain, which in turn reduces the central nervous depressive activity of anesthetics.