大鼠内脏及压力感受器神经元的性别差异  

Gender differences between visceral and baroreceptor afferent neurons of rats

作　　者：乔国芬[1,2] 龚冬梅[2] 赵瑞波[3] 李柏岩[2] 付宜利[1] 

机构地区：[1]哈尔滨工业大学生物医学工程研究中心,黑龙江哈尔滨150001 [2]哈尔滨医科大学药学院药理学教研室 [3]哈尔滨医科大学基础医学院病理学教研室,黑龙江哈尔滨150081

出　　处：《中国药理学通报》2009年第5期636-641,共6页Chinese Pharmacological Bulletin

基　　金：黑龙江省教育厅科研基金资助课题(No11531111)

摘　　要：目的观察大鼠有髓和无髓内脏/主动脉压力感受器(ABN)传入神经元电生理及神经解剖学的性别差异。方法制备分离神经元、迷走神经-神经节切片,荧光标记主动脉减压神经(ADN),鉴别ABN,全细胞电流钳记录神经元动作电位(AP),结合电子显微镜观察,分析ADN各型纤维存在、分布及电生理特性之间的性别差异。结果♂♀大鼠结状神经节存在A-和C-型神经元,AP相关参数♂♀间差异无显著性。除A-和C-型外,♀大鼠还观察到一种传导速度快、低阈值高兴奋性Ah-型髓鞘化ABN;电镜结果显示,ADN有髓纤维出现频率(~25%)与电生理结果一致。Ah-型诱发放电频率(20 Hz^40 Hz)低于A-型(40 Hz^150 Hz,P<0.01),但高于C-型。去卵巢♀大鼠,A-和C-型兴奋性变化不明显,但Ah-型放电频率降低(2~5 Hz,P<0.01),雌激素恢复去卵巢♀大鼠Ah-型放电频率到正常水平,且作用可被雌激素特异性受体阻断剂阻断。结论仅见于♀大鼠内脏和压力感受器传入通路的Ah-型有髓纤维,其数量与A-型相似,表现为低阈值高兴奋性,可能在维持♀动物较低动脉血压的生理过程中发挥重要作用。Aim To investigate the gender differences in electrophysiology and neuroanatomy of myelinated and unmyelinated visceral and baroreceptor afferent neurons （VANs and ABNs） of adult rats. Methods VANs and ABNs were isolated enzymatically and Vagus-nodose slice preparation was also applied in this study. For identification of ABNs, aortic depressor nerve （ADN） was labeled using fluorescent dye. Whole-cell patch technique was used to record action potential （AP）. Electronic microscopy was selected for morphological analysis of ADN. Results （ 1 ） A-and C-type VANs were identified and significant differences of AP discharge profiles between female and male were not established; （2） except for the traditionally classified A-and C-types, myelinated Ah-type VGNs were also identified with faster conduction velocity, lower firing threshold, and higher neuronal excitability. Importantly, these Ah-types were found in female rats with a similar frequency like A-types but rarely seen in males. （3） Ah-type ABNs were also identified by fluorescence. （4） Morphological data showed that myelinated fiber in ADN was - 25 % of total and this result was consistent with our electrophysiological data. （5） Firing frequency of Ah-types （20 - 40 Hz） was lowered than that of A-types （40 - 150 Hz,P 〈 0. 01 ）, but significantly higher than that of C-types （ 〈 10 Hz, P 〈0. 01 ）. （6） Firing frequency was dramatically reduced （ 2 ～ 5 Hz, P 〈 0. 01 ） in Ah-types but not in Aand C-types from ovariectomized females （OVX）. This reduced firing frequency was completely restored in the presence of 1.0μmol·L^-1 of 17β-estradiol （E2） and blocked by E2 specific receptor antagonist ICI 182 780. Conculsion Myelinated Ah-type VANs and ABNs identified in visceral afferent pathway of female rats show a similar in a frequency distribution as A-types, lower firing frequency, and higher neuronal excitability. All these features may play, at least in part, an important role in maintaining lower

关 键 词：传入纤维 神经元 动作电位 主动脉 减压神经 性 别差异 

分 类 号：R-332[医药卫生] R195