Effects and Mechanisms of Electroacupuncture at Zhongwan （CV12） on Gastric Nociceptive Response Induced by Gastric Acid Stimulation in Rats / 中医杂志

ABSTRACT

ObjectiveTo observe the effects of electroacupuncture at Zhongwan （CV12） on gastric nociceptive response induced by gastric acid stimulation and explore the underlying mechanisms associated with nuclei of the medullary viscerosensory and visceral motor neurons. MethodsTwenty SD rats were given intragastric administration of 0.5 mol/L diluted hydrochloric acid （0.5 ml/100 g） to induce gastric nociceptive response induction. Eight rats were randomly selected to record the gastric slow wave （GSW） area under the curve， and extracellular discharge frequency of neurons in the nucleus of the solitary tract （NTS） and dorsal motor nucleus of the vagus nerve （DMV） before intragastric administration and at 1， 5， 10， 15， 20， 25， 30， 35， 40， 45， 50， 55， and 60 minutes after intragastric administration. The remaining 12 rats received electroacupuncture intervention at Zhongwan within 5 to 25 minutes after intragastric administration of diluted hydrochloric acid， with a duration of one minute. The GSW area under the curve and extracellular discharge frequency of NTS and DMV neurons were compared between the 1-minute intervals before and after electroacupuncture intervention. ResultsCompared to the baseline before intragastric administration， the area under the curve of GSW significantly increased at 1， 5， 10， 15， 20， and 25 minutes after intragastric administration， and the extracellular discharge frequency of excitatory neurons in the NTS （accounting for 90%， 57/63） significantly increased at 1， 5， 10， 15， 20， 25， 30， 35， and 40 minutes， both reaching peak values at 1 minute after intragastric administration （P＜0.01 or P＜0.05）. The extracellular discharge frequency of inhibitory neurons in the DMV （accounting for 91%， 20/22） showed a non-significant increase at 1 minute after intragastric administration （P＞0.05）， but significantly decreased at other timepoints （P＜0.05）. Compared to the baseline before electroacupuncture intervention， the GSW area under the curve and the extracellular discharge frequency of excitatory neurons in the NTS significantly decreased （P＜0.05）， while the extracellular discharge frequency of inhibitory neurons in the DMV showed no significant difference （P＞0.05）. ConclusionElectroacupuncture at Zhongwan can improve gastric nociceptive response induced by gastric acid stimulation， possibly by reducing the transmission of visceral sensation and decreasing the excitability of NTS neurons in the medulla.