γ-氨基丁酸A受体对在体前庭内侧核神经元调控的电生理研究  

Modulation of γ-aminobutyric acid receptor on medial vestibular nucleus neurons in vivo

作　　者：汪绪武[1] 孔维佳[1] 

机构地区：[1]华中科技大学同济医学院附属协和医院耳鼻咽喉科

出　　处：《中华耳鼻咽喉头颈外科杂志》2005年第11期830-834,共5页Chinese Journal of Otorhinolaryngology Head and Neck Surgery

基　　金：国家杰出青年基金资助项目(39925035);国家自然科学基金资助项目(30070809);教育部高等学校骨干教师资助计划(200065)

摘　　要：目的探讨γ氨基丁酸(γaminobutyricacid,GABA)不同受体在前庭核神经元电活动调控中的作用。方法选用健康雄性Wistar大鼠26只,以在体微电泳方法检测γ氨基丁酸、荷包牡丹碱(bicuculine,BIC,γ氨基丁酸A拮抗剂)和2羟基巴氯芬(2hydroxysaclofen,SAC,γ氨基丁酸B拮抗剂)对大鼠前庭内侧核神经元自发放电的影响。结果记录了42个前庭内侧核神经元对γ氨基丁酸的反应,以10、30、50nA的电流微电泳γ氨基丁酸,放电频率的减少呈明显的量效关系,平均放电频率(x±s)由基础频率的(14.8±5.6)次/s分别减至(8.7±3.4)次/s、(4.1±1.6)次/s和(2.2±1.1)次/s;观察了37个前庭内侧核神经元对BIC的反应,微电泳BIC后,86.5%(32/37)神经元出现兴奋性反应,13.5%(5/37)无反应;以10、30、50nA的电流电泳BIC,放电频率分别由基础状态下的(15.3±6.3)次/s分别增加至(16.8±7.1)次/s、(25.9±10.1)次/s和(32.7±11.3)次/s,呈明显的量效关系,并能完全阻断γ氨基丁酸的抑制性效应;但微电泳SAC对大多数前庭内侧核神经元无明显影响,对γ氨基丁酸的阻断作用也不明显。结论γ氨基丁酸能明显抑制前庭内侧核神经元自发放电,这种作用主要是通过γ氨基丁酸A受体介导的。Objective To investigate modulation of γ-aminobutyric acid （GABA） and its receptors on medial vestibular nucleus neurons in vivo. Methods Twenty-six male Wistar rats were used. γ-aminobutyric acid,bicuculine （BIC, γ-aminobutyric acid A receptor antagonist） and 2-hydroxysaclofen （SAC, γ-aminobutyric acid B receptor antagonist） were microiontophoreted on medial vestibular nucleus （MVN） neurons to determine the effects of γ-aminobutyric acid and its antagonists on the neuronal firing rates of medial vestibular nucleus in rats in vivo. Results Microiontophoretic application of γ-aminobutyric acid at 10, 30, 50 nA electric current produced inhibitory responses on 42 MVN neurons, these responses were dose-dependent decreases, firing rates （x^-± s ） of MVN neurons decreased form （ 14. 8 ± 5.6 ） times/s to （8.7 ±3.4） times/s, （4. 1 ± 1. 6） times/s and （2.2± 1.1 ） times/s respectively; microiontophoretic application of bicuculine in 37 MVN neurons, 86. 5% （32/37） neurons produced excitatory responses, 13.5% （5/37） neurons didn＇t responsed, firing rates of MVN neurons increased form （ 15.3 ±6. 3） times/s to （ 16. 8 ± 7. 1 ） times/s, （25.9 ± 10. 1 ） times/s and （32. 7 ± 11.3） times/s respectively at 10, 30, 50 nA electric current, which were dose-dependent increases, and the inhibitory responses of γ-aminobutyric acid on MVN neurons were blocked by bicuculine completely; however, microiontophoretic application of 2-hydroxysaclofen didn＇t produced responses as bicuculine did. Conclusions Modulation of γ-aminobutyric acid on medial vestibular nucleus neurons was mediated by γ-aminobutyric acid A receptor in vivo.

关 键 词：微电泳 受体 Γ-氨基丁酸 前庭内侧核 

分 类 号：Q424[生物学—神经生物学]