Evaluation of the Effect of Metoclopramide on Acupuncture and Electro-acupuncture Analgesia – A Blind and Controlled Study in Rats

Metoclopramide is an antagonist that is selective of dopamine DA2-receptors. In high doses it appears to have antagonist properties also towards DA1 receptors. It has been demonstrated that the dopaminergic system is closely correlated to opioid actions; in particular it has been observed that the destruction of DA2 receptors in rats increases analgesia by μ and k1 agonists. The role of dopamine on acupuncture-induced analgesia is not fully defined; the data available is scarce and contrasting. The aim of the present study was to verify whether the administration of metoclopramide potentiates the analgesic efficacy of manual and electro-acupuncture in the rats.