OBJECTIVE: To study on mechanisms of acupuncture in relieving visceral pain. METHODS: In SD rats CRD was used as noxious visceral stimuli. Activities of spinal dorsal horn wide dynamic (WDR) neurons of L1-L13 were recorded by extracellular microelectrode technique. Acupuncture was given at ipsi-lateral and contra-lateral Zusanli (ST 36) of the same segmental innervation of rectum and colon. RESULTS: Visceral noxious afferent could significantly activate spinal dorsal horn convergent neurons, and mechanical stimulation of contra-lateral body surface and hand acupuncture at Zusanli (ST 36) could inhibit this noxious response. When the spinal cord was acutely blocked, the inhibiting CRD effect of needling CRD effect of needling contra-lateral Zusanli (ST 36) completely disappeared. CONCLUSION: Acupuncture and visceral noxious afferent signals converge and interact each other in spinal level, and acupuncture at acupoint can inhibit the spinal dorsal horn neuron respon se activated by visceral noxious afferent and this action needs the participation of the center above the spinal cord.
OBJECTIVE: To study on mechanisms of acupuncture in relieving visceral pain. METHODS: In SD rats CRD was used as noxious visceral stimuli. Activities of spinal dorsal horn wide dynamic (WDR) neurons of L1-L13 were recorded by extracellular microelectrode technique. Acupuncture was given at ipsi-lateral and contra-lateral Zusanli (ST 36) of the same segmental innervation of rectum and colon. RESULTS: Visceral noxious afferent could significantly activate spinal dorsal horn convergent neurons, and mechanical stimulation of contra-lateral body surface and hand acupuncture at Zusanli (ST 36) could inhibit this noxious response. When the spinal cord was acutely blocked, the inhibiting CRD effect of needling CRD effect of needling contra-lateral Zusanli (ST 36) completely disappeared. CONCLUSION: Acupuncture and visceral noxious afferent signals converge and interact each other in spinal level, and acupuncture at acupoint can inhibit the spinal dorsal horn neuron respon se activated by visceral noxious afferent and this action needs the participation of the center above the spinal cord.