GABAB受体激动剂巴氯芬对大鼠中脑导水管周围灰质兴奋性及抑制性突触的作用  

Effect of GABA_B receptor agonist baclofen on excitatory and inhibitory synapses of ventrolateral periaqueductal gray in rats

作　　者：邵采凤 张雯玮 胡朝婷 王冉超 接玉 赵昶昀 陈茜 杨鲲 SHAO Cai-feng;ZHANG Wen-wei;HU Chao-ting;WANG Ran-chao;JIE Yu;ZHAO Chang-yun;CHEN Qian;YANG Kun(Dept of Anatomy,School of Medicine,Jiangsu University,Zhenjiang Jiangsu 212013,China;Dept of Anesthesiology,Affiliated People’s Hospital of Jiangsu University,Zhenjiang Jiangsu 212002,China;Undergraduate Students of Class 2015,School of Medicine,Jiangsu University,Zhenjiang Jiangsu 212013,China;Undergraduate Students of Class 2016,School of Medicine,Jiangsu University,Zhenjiang Jiangsu 212013,China)

机构地区：[1]江苏大学医学院解剖学教研室,江苏镇江212013 [2]江苏大学附属人民医院麻醉科,江苏镇江212002 [3]江苏大学医学院,江苏镇江212013

出　　处：《中国药理学通报》2018年第11期1511-1515,共5页Chinese Pharmacological Bulletin

基　　金：国家自然科学基金资助项目(No 30000052);江苏省研究生科研创新计划项目(No KYCX17-1800);江苏大学大学生实践创新训练项目(No 201810299126X)。

摘　　要：目的研究大鼠中脑导水管周围灰质(periaqueductal gray, PAG)内饱和及非饱和浓度的GABA_B受体激动剂对兴奋性突触及抑制性突触作用的异同。方法利用全细胞膜片钳记录方法在成年大鼠PAG的急性横切薄片记录其腹外侧区神经元。结果饱和浓度的GABA_B受体激动剂巴氯芬(baclofen,5μmol·L^(-1))对上述两类突触的抑制效果无统计学差异,而非饱和浓度的巴氯芬(0.1μmol·L^(-1))对上述两类突触的作用有差异,0.1μmol·L^(-1)巴氯芬对抑制性突触的抑制效应明显大于其对兴奋性突触的抑制。与之相对应,0.1μmol·L^(-1)巴氯芬对单个PAG神经元的兴奋性显示增加作用,而非抑制作用。结论饱和浓度的GABA_B受体激动剂巴氯芬抑制两类突触的比率无差别,而非饱和浓度的巴氯芬对抑制性突触的抑制作用比其对兴奋性突触的抑制效率高,此结果可能解释了PAG注射不同浓度巴氯芬引起不同行为学反应的原因。Aim To investigate the possible difference between glutamatergic synapses and GABAergic synapses in the ventrolateral periaqueductal gray(vlPAG)when GABAB receptor agonist is at nonsaturating concentration or saturating concentration.Methods We employed whole cell patch-clamp recordings on acute PAG slices from adult rats.Results Glutamatergic synapses were less sensitive to baclofen,a putative GABAB receptor agonist,than that of GABAergic synapses,but only at nonsaturating concentration(0.1μmol·L^-1).On the contrary,saturating concentration of baclofen(5μmol·L^-1)inhibited both glutamatergic and GABAergic synapses to a similar ratio.Accordingly,low concentration of baclofen increased,while high concentration decreased the excitability of postsynaptic vlPAG neurons.Conclusions The overall action of baclofen in vlPAG depends on its concentrations.Since vlPAG plays an important role in reducing pain modulation system,the different concentrations of GABA may induce its varying actions on modulation.

关 键 词：GABAB受体 兴奋性突触 抑制性突触 全细胞记录 中脑导水管周围灰质 大鼠 

分 类 号：R-332[医药卫生] R322.81