[Effects of acupuncture at "Zusanli" (ST 36) on sensitive neurons of gastric distention in LHA-FN circuit in rats].

OBJECTIVE: To observe the regulation effects of acupuncture at "Zusanli" (ST 36) on sensitive neurons of gastric distention (GD) in lateral hypothalamus area (LHA) and fastigial nuclear (FN) circuit, and to explore the central mechanism of acupuncture for gastric function. METHODS: A total of 101 rats were randomly assigned into a LHA group (50 rats) and a FN group (51 rats). Gastric distension surgery was performed in all the rats. According to the stereotaxic atlas of rat brain, the LHA and FN were located, followed by craniotomy. The endocranium was removed to exposure brain tissue, and warm paraffin oil was used to prevent desiccation. The electrical activities of neurons were probed by glass microelectrode to perform extracellular recording. The electrical activities of GD sensitive neurons in LHA were observed in LHA group, while those in FN were observed in FN group. One min after the electrical signal of neurons was recorded, acupuncture was given at left "Zusanli" (ST 36) with mild reinforcing and attenuating technique, 120~180 times/min for 1 min. The effects of acupuncture at "Zusanli" (ST 36) on spontaneous discharge of GD sensitive neurons in LHA and FN were observed. RESULTS: (1) Totally 54 LHA neurons of spontaneous discharge in LHA group and 85 FN neurons in FN group were recorded. GD-excitatory (GD-E) neurons were mainly in the LHA group (46.3%) and GD-non-response (GD-N) neurons were mainly in the FN group (54.12%). The average discharge frequency of GD-N neurons was (39.03±14.91) spikes/s, that of GD-E neurons was (19.67±12.08) spikes/s, and that of GD-inhibitory (GD-I) neurons was (28.76±7.26) spikes/s, which were statistically different from those before GD (all P<0.01). (2) In LHA group, acupuncture excited the activity of GD-E neurons, and inhibited the activity of GD-I neurons (P<0.05); in FN group, acupuncture excited the activity of GD-I neurons, but showed no effect on GD-E neurons (P<0.01). CONCLUSIONS: The signal of GD and acupuncture could converge in LHA and FN; acupuncture presented different regulation effects on identical type of GD-sensitive neurons in different nuclear groups; LHA-FN circuit might participate in central integration mechanism of acupuncture on gastric function.