[Role of hippocampus NMDAR subunits in electroacupuncture at "Zhongwan" (CV 12) and "Weishu" (BL 21) for gastric motility].

Objective: To observe the effects of electroacupuncture (EA) on gastric motility, protooncogene c-fos and hippocampus N-methyl-D-aspartate (NMDA) receptor subunits in rats with functional dyspepsia (FD), and to discuss the molecular mechanism of hippocampal in EA at "Zhongwan" (CV 12) and "Weishu" (BL 21) for gastric motility.
Methods: Eighty-four Sprague Dawley (SD) rats were randomly divided into a normal group, a model group, a Zhongwan group, a Weishu group, an acupoint combination group and a non-acupoint group, 14 rats in each one. Except for the normal group, FD model were established by moderate tail-clipping infuriation method and irregular feeding. The rats in the Zhongwan group, Weishu group, acupoint combination group and non-acupoint group were treated with EA at corresponding acupoints, 20 min per treatment, once a day for 7 days. The rats in the normal group and the model group received no treatment; grabbing and fixation were applied in the model group. The stress transducer was used to record gastric motion waveforms; immunohistochemistry method was used to detect the expression of c-fos in hippocampus; Western blot method was used to detect the expression of NMDA receptor subunits NR1, NR2A and NR2B in hippocampus.
Results: Compared with the normal group, the gastric motility range was decreased ( P <0.05), and the expression of hippocampus NR2A was reduced and the levels of NR1 and NR2B were increased in the model group ( P <0.05), however, hippocampus c-fos expression was not significant different between the normal group and the model group ( P >0.05). Compared with the model group, the gastric motility range was increased, the expression of hippocampus c-fos and expression of hippocampus NR2A was increased but expressions of NR1 and NR2B were reduced in the Weishu group, Zhongwan group and acupoint combination group ( P <0.05). Besides, the differences of gastric motility range and expression of hippocampus c-fos, NR1, NR2A and NR2B between the model group and the non-acupoint were not significant ( P >0.05). Compared with the Zhongwan group and the Weishu group, the gastric motility range was increased, the expression of hippocampus c-fos and NR2A was increased but the expression of NR1 and NR2B was reducedin the acupoint combination group ( P <0.05). There was no significant difference in the frequency of gastric motility among the groups ( P >0.05).
Conclusion: EA at "Zhongwan" (CV 12) and "Weishu" (BL 21) could increase gastric motility of FD rats, which is likely to be related with activating hippocampal neurons, upregulating the level of NR2A and downregulating NR1 and NR2B.