Function of Nucleus Ventralis Posterior Lateralis Thalami in Acupoint Sensitization Phenomena

To observe the effect of electroacupuncture (EA) on nucleus ventralis posterior lateralis (VPL) thalami activated by visceral noxious stimulation and to explore the impact of EA on the mechanism of acupoint sensitization under a pathological state of the viscera, EA was applied at bilateral “Zusanli-Shangjuxu” acupoints. The discharge of VPL neurons was response to EA increased after colorectal distension (CRD). The stimulation at “Zusanli-Shangjuxu” acupoints enhanced discharge activity of VPL neurons under CRD-induced visceral pain. The frequency of neuronal discharge was associated with the pressure gradient of CRD which showed that visceral noxious stimulation may intensify the body's functional response to stimulation at acupoints.