清醒大鼠下丘脑室旁核内GABA对压力感受性反射的影响  

Effect of GABA in the hypothalamic paraventricular nucleus on regulation of baroreflex in conscious rats

作　　者：邴艳华[1] 高晓磊[1] 尹桂东[1] 金元哲[1] 金清华[1] 

机构地区：[1]延边大学医学部基础医学院生理学与病理生理学教研部,吉林延吉133000

出　　处：《中国现代医学杂志》2010年第7期995-999,共5页China Journal of Modern Medicine

基　　金：国家自然科学基金(No:30460041);延边大学研究生科研基金(No:2007-10)

摘　　要：目的探讨下丘脑室旁核(PVN)内γ-氨基丁酸(GABA)对压力感受性反射的作用及其机制。方法本实验在给清醒自由活动大鼠静脉注射苯肾上腺素诱发压力感受性反射的条件下,用脑部微量透析法和高效液相色谱法测定PVN区细胞外液中的GABA含量变化,并利用两种GABA受体阻断剂进一步探讨其具体的作用机制。结果①静脉注射苯肾上腺素诱发压力感受性反射时,PVN区域细胞外液中的GABA水平出现明显的增加,增加到注射前的(225.14±65.72)%(P<0.05);②PVN局部边灌流GABAA受体阻断剂Bicuculline,边用苯肾上腺素诱发压力感受性反射,血压的增加幅度显著高于对照组(P<0.05),而心率下降幅度与对照组比无明显差异(P>0.05),导致压力感受性反射敏感性(△HR/△MAP)明显低于对照组(P<0.05);③PVN局部灌流GABAB受体阻断剂Saclofen对压力感受性反射中的血压和心率的变化值以及压力感受性反射敏感性均未产生明显的影响。结论静脉注射苯肾上腺素引起PVN局部GABA释放,可能通过GABAA受体对压力感受性反射起易化作用。【Objective】To investigate the possible involvement of γ-aminobutyric acid（GABA） in the hypothalamic paraventricular nucleus（PVN） in the central regulation of baroreflex.【Methods】Baroreflex was induced by intravenous injection of phenylephrine,then the extracellular concentration of GABA in the PVN region was measured by microdialysis and high performance liquid chromatography（HPLC） techniques in conscious rats,and the blood pressure（BP） and heart rate（HR） were recorded simultaneously.Next,bicuculline（an antagonist of GABAA receptor） or saclofen（an antagonist of GABAB receptor） were directly perfused in the PVN region during baroreflex,then the sensitivity of baroreflex was examined.【Results】 The extracellular levels of GABA in the PVN region showed an immediate increase during baroreflex,which reached to（225.14±65.72）% of the basal levels（P 0.05）.Direct perfusion of bicuculline in the PVN region significantly decreased the baroreflex sensitivity,whereas saclofen did not influence the baroreflex sensitivity.【Conclusion】Our results suggest that injection of phenylephrine elicits a local release of GABA in the PVN region,which may act via GABAA receptor to produce a facilitative effect on baroreflex.

关 键 词：下丘脑室旁核 压力感受性反射 GABA 清醒大鼠 

分 类 号：Q426[生物学—神经生物学] R338.27[生物学—生理学]