BINDING-SITES OF MU-RECEPTOR INCREASED WHEN ACUPUNCTURE ANALGESIA WASENHANCED BY DROPERIDOL - AN AUTORADIOGRAPHIC STUDY

AIM: To study if mu receptor participates in the process of potentiati on of droperidol (Dro) on acupuncture analgesia (AA). METHODS: Autorad iographic technic was used. Ohmefentanyl, a highly selective ligand of mu receptors, was used in radio-receptor binding assay in Sprague-Daw ley rat brain sections. RESULTS: The binding sites of [beta-H-3, p-ben zoyl-H-3]ohmefentanyl were increased greatly in many nuclei of rat bra in after AA, and were further increased when AA was enhanced by Dro. H igher increase was seen in caudate nucleus, accumbens, periaqueductal gray (PAG), interpeduncular nucleus, amygdala (P<0.01 vs rats treated with electroacupuncture alone); moderate increase was noted in thalamu s, lateral area of hypothalamus, spinal dorsal horn (P<0.01 or 0.05); slight increase appeared in septum, preoptic area, hippocampus, substa ntia nigra (P<0.05). CONCLUSION: Mu opioid receptors mediated the Dro- induced enhancement of AA.