Effect of grouped ST36 or RN12 on gastric motility and sensation

Abstract

Objective: To investigate the effects of paired ST36 and RN12 acupuncture stimulation on gastric motility and the firing rate of responsible neurons in anesthetized rats. Methods: Using electrophysiological methods, we measured the effects of acupuncture at RN12, ST36, or RN12+ST36 on gastric motility as well as nerve discharges from the gastric sympathetic, vagal nerve, and wide dynamic range (WDR) neurons in the spinal dorsal horn T7-9 in anesthetized rats. Results: 1) Acupuncture at RN12 inhibited gastric motility (83.84±4.49)% and vagal nerve discharge (65.64±5.67)%, but promoted sympathetic nerve activity (243.70±40.67)%; acupuncture at ST36 induced opposing effects on gastric motility (111.31±2.01)% and vagal nerve discharge (166.98±15.92)%. Interestingly, acupuncture at RN12+ST36 together yielded effects similar to that of acupuncture at RN12 alone (93.59±2.05)%, (54.52±7.12)%. 2) WDR neuron discharges induced by gastric distension were inhibited by acupuncture at RN12 (194.56 ± 18.79)%. However, acupuncture at ST36 induced a more significant inhibitory effect. Conclusion: Acupuncture at RN12 inhibits gastric motility by activation of the sympathetic reflex at the spinal level; acupuncture at ST36 promotes gastric motility by activation of the parasympathetic reflex at the supraspinal level, and acupuncture at RN12+ST36 produces a similar decrease in gastric motility as RN12 stimulation alone. Both acupoints decrease the effect of noxious gastric distention on WDR neuron activity, but paired RN12+ST36 stimulation does not significantly affect WDR neuron discharge.