电针“四白”和“颧髎”激活小鼠躯体感觉运动皮层的兴奋性神经元

Effect of electroacupuncture stimulation of “Sibai”(ST2) and “Quanliao”(SI18) on excitatory neurons of sensorimotor cortex in mice

目的:探讨电针“四白”和“颧髎”对小鼠躯体感觉皮层和初级运动皮层神经元的激活状态及其分型的影响。方法:雄性C57BL/6J小鼠随机分为空白组和电针组,每组6只。电针组电针“四白”和“颧髎”,干预30 min。采用免疫荧光染色法观察躯体感觉皮层和初级运动皮层即刻早期基因c-Fos的阳性细胞密度,以及c-Fos阳性细胞和钙/钙调蛋白依赖性蛋白激酶Ⅱ(CaMKⅡ)/γ-氨基丁酸(GABA)共表达细胞的百分比,分析电针后躯体感觉皮层和初级运动皮层c-Fos神经元的类型。另取10只小鼠,采用光纤钙成像技术分别观察电针前后躯体感觉皮层和初级运动皮层兴奋性神经元钙活动的变化。结果:在躯体感觉皮层和初级运动皮层中,电针组的c-Fos阳性细胞密度显著高于空白组(P<0.05)。在躯体感觉皮层和初级运动皮层中,电针组c-Fos和CaMKⅡ共表达细胞百分比显著高于空白组(P<0.01)。光纤记录钙成像结果显示,与电针前相比,电针期间躯体感觉皮层和初级运动皮层兴奋性神经元的自发钙活动显著上升(P<0.01);电针后,其自发钙活动较电针期间显著降低(P<0.05)。结论:在生理状态下,针刺“四白”和“颧髎”能够有效激活躯体感觉皮层和初级运动皮层的兴奋性神经元。

Objective To observe the activation state and neuronal types of somatosensory cortex and the primary motor cortex induced by electroacupuncture(EA) stimulation of “Sibai”(ST2) and “Quanliao”(SI18) acupoints in mice.Methods Male C57BL/6J mice were randomly divided into blank control and EA groups,with 6mice in each group.Rats of the EA group received EA stimulation(2 Hz,0.6 mA) at ST2 and SI18 for 30 minutes.Samples were collected after EA intervention,and immunofluorescence staining was performed to quantify the expression of the c-Fos gene(proportion of c-Fos positive cells) in the somatosensory cortex and primary motor cortex.The co-labelled cells of calcium/calmodulin-dependent protein kinase Ⅱ (CaMK Ⅱ ) and gamma-aminobutyric acid(GABA) in the somatosensory cortex and primary motor cortex were observed and counted by using microscope after immunofluorescence staining.Another 10 mice were used to detect the calcium activity of excitatory neurons in the somatosensory cortex and primary motor cortex by fiber photometry.Results In comparison with the blank control group,the number of c-Fos positive cells,and the proportion of c-Fos and CaMK Ⅱ co-labelled cells in both the somatosensory cortex and primary motor cortex were significantly increased after EA stimulation(P<0.05).No significant changes were found in the proportion of c-Fos and GABA co-labeled cells in both the somatosensory cortex and primary motor cortex after EA.Results of fiber optic calcium imaging technology showed that the spontaneous calcium activity of excitatory neurons in both somatosensory cortex and primary motor cortex were obviously increased during EA compared with that before EA(P<0.01),and strikingly reduced after cessation of EA compared with that during EA(P<0.05).Conclusion Under physiological conditions,EA of ST2 and SI18 can effectively activate excitatory neurons in the somatosensory cortex and primary motor cortex.