I_A和I_h对鳌虾口胃神经节幽门节律的调节  

Regulation of pyloric rhythm by I_A and I_h in crayfish stomatogastric ganglion

作　　者：匡国晖[1] 刘一辉[1] 任维[1] 

机构地区：[1]陕西师范大学生命科学学院,西安710062

出　　处：《生理学报》2012年第3期275-281,共7页Acta Physiologica Sinica

基　　金：supported by the National Natural Science Foundation of China (No. 30900443)

摘　　要：甲壳类动物的口胃神经节(stomatogastric ganglion, STG)由30个神经元组成,产生幽门节律,是研究中枢模式发生器(central pattern generator, CPG)的常用模型。幽门节律的维持与调控,不仅与STG神经元网络中单个神经元的特性有关,也与整个网络的连接及其性质相关。已有研究观察到STG网络中不同神经元上存在瞬时外向钾电流(transient potassium current, I_A)与超极化激活阳离子电流(hyperpolarization-activated cation current, I_h),但这两种电流对整个STG网络节律的维持与调控作用仍不清楚。本实验采用鳌虾STG离体标本神经纤维记录,通过施加特异性阻断剂来研究I_A和I_h对鳌虾STG幽门节律性放电的调节作用。结果显示:施加I_A特异性阻断剂4AP (2 mmol/L)后,幽门节律周期变短(P < 0.01),PD (pyloric dilator)细胞放电时程占整个三相周期的比率增加(P < 0.01),LP (lateral pyloric)细胞放电时程不变(P > 0.05)但相位滞后,PY (pyloric)细胞放电时程占整个三相周期的比率减小(P < 0.05)且相位滞后,三相顺序没有改变;施加Ih特异性阻断剂ZD7288 (100 μmol/L)后,幽门节律周期变短(P < 0.01),PD细胞放电时程占整个三相周期的比率增加(P < 0.01),LP细胞放电时程占整个三相周期的比率增加(P < 0.01)且相位滞后,PY细胞放电时程占整个三相周期的比率减小(P < 0.01)且相位滞后,三相顺序没有改变。上述结果表明,I_A和I_h对鳌虾STG幽门节律有重要的调节作用,进而影响到幽门活动的生理功能。The stomatogastric ganglion（STG） of shellfish includes 30 neurons and produces pyloric rhythms.It is the common model to study central pattern generator（CPG）.Regulation of pyloric rhythms not only is related to the property of single neurons in STG but also depends on the connections and property of the whole neuronal network.It has been found that transient potassium current（I_A） and hyperpolarization-activated cation current（I_h） exist in certain types of neurons of STG.However,roles played by these two currents in maintaining and regulating the pyloric rhythms are unknown.In the present study,in vitro electrophysiological recordings were performed on crayfish STG to examine the role played by I_A and I_h in regulation of pyloric rhythm.4AP（2 mmol/L）,a specific inhibitor of I_A,caused a decrease in pyloric cycle（P 〈 0.01）,an increase in PD（pyloric dilator） ratio,a decrease in PY（pyloric） ratio（P 〈 0.01） and delay of phases of LP and PY firing.ZD7288（100 μmol/L）,a specific inhibitor of I_h,caused a decrease in pyloric cycle（P 〈 0.01）,an increase in PD ratio（P 〈 0.01）,an increase in LP（lateral pyloric） ratio（P 〈 0.01）,a decrease in PY ratio（P 〈 0.01） and delay of phases of LP and PY firing.These results indicate that I A and I h play important roles in regulating pyloric rhythms in crayfish STG.

关 键 词：中枢模式发生器 口胃神经节 幽门节律 4AP ZD7288 

分 类 号：Q42[生物学—神经生物学]