下丘脑GABA和烫伤大鼠心血管功能改变的关系

The Relationship between Hypothalamus GABA Level and Cardio-vascular Functions in Scalded Rats

目的：首先观察烫伤早期大鼠下丘脑γ－氨基丁酸及其受体的改变，进一步通过阻断烫伤大鼠下丘脑室旁核γ－氨基丁酸的作用，观察其心血管指标和存活时间的改变。方法：采用脑组织游离氨基酸自动分析法测定烫伤大鼠下丘脑氨基酸递质相对含量；运用神经元突膜结合受体法测定核γ－氨基丁酸受体功能；制备大鼠30％总体表面积Ⅲ度烫伤模型；借助脑立体定向仪行室旁核内注射；运用四导生理仪记录血压和心肌力学指标。结果：烫伤早期大鼠下丘脑γ－氨基丁酸含量明显增加，谷氨酸减少，其它氨其酸递质含量无明显变化；γ－氨基丁酸受体最大结合容量明显增加，平衡解离常数无明显改变。烫伤大鼠下丘脑室旁核γ－氨基丁酸作用的阻断可明显回升其血压、左心室收缩压、左心室内压最大变化速率和延长存活时间。结论：提示中枢γ－氨基丁酸对大鼠烫伤早期心血管功能有影响，部位可能在下丘脑室旁核。

Change in the level of γ - amino - butyric acid (GANA) and its receptor in hypothalamus of scalded rats at the early stage was observed and then the effect of GABA in paraventricular nucleus of hypothalamus was blocked to observe changes in cardiovascular indexes and surviving timeof the scalded rats. The results revealed that at early stage post scald, GABA level in rat hypothalamusincreased significantly, glutamic acid level decreased, while other amino acid transmitter level had nosignificant change. The maximal combining capacity of GABA receptor increased significantly, whilethe dissociation constant kept no significant change. Blockge of the effect of GABA in paraventricularnucleus of hypothalamus of scalded rats resulted in significant increase of blood pressure, left ventriclesystolic pressure and left ventricular pressure maximal nuctuation rate and prolonging of survival time.These results suggest that central GABA level can affect the function of cardio - vascular system ofscalded rats at early stage and the active site may be paraventricular nucleus of hypothalamus.