Hypothalamic GABA suppresses sympathetic outflow to the cardiovascular system.
Hypothalamic GABA suppresses sympathetic outflow to the cardiovascular system.
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DOI：
10.1152/ajpregu.1988.254.4.r680
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发表时间：
1988-04
期刊：
影响因子：
--
通讯作者：
J. Wible;Friedrich C. Luft;J. Dimicco
中科院分区：
文献类型：
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作者：
J. Wible;Friedrich C. Luft;J. Dimicco
我们研究了改变大鼠下丘脑后部 GABA 能张力对心血管的影响。动物配备了放置在下丘脑后部的慢性引导插管、动脉和静脉导管以及内脏神经上的双极电极。将突触后γ-氨基丁酸（GABA）拮抗剂荷包牡丹碱和印防己毒素双侧显微注射到清醒大鼠的下丘脑后部，可迅速增加心率、血压和交感神经活动。将 GABA 激动剂蝇蕈醇显微注射到同一区域可降低清醒大鼠的心率、血压和交感神经活动。相比之下，将蝇蕈醇注入麻醉大鼠下丘脑后部并不能改变心率或血压。我们得出的结论是：1）下丘脑后部包含一个由 GABA 能张力变化调节的交感兴奋系统，2）强直性 GABA 能抑制足以完全抑制麻醉动物但清醒大鼠中下丘脑交感兴奋系统的活性。
We studied the cardiovascular effects of altering GABA-ergic tone in the posterior hypothalamus in rats. Animals were equipped with chronic guide cannulas placed in the posterior hypothalamus, arterial and venous catheters, and a bipolar electrode on the splanchnic nerve. Microinjected bilaterally into the posterior hypothalamus in conscious rats, the postsynaptic gamma-aminobutyric acid (GABA) antagonists bicuculline methiodide and picrotoxin rapidly increased heart rate, blood pressure, and sympathetic nerve activity. Microinjection of the GABA agonist muscimol into this same region decreased heart rate, blood pressure, and sympathetic nerve activity in conscious rats. In contrast, muscimol infused into the posterior hypothalamus of anesthetized rats failed to alter heart rate or blood pressure. We conclude that 1) the posterior hypothalamus contains a sympathoexcitatory system that is modulated by changes in GABA-ergic tone and 2) tonic GABA-ergic inhibition is sufficient to completely suppress the activity of this hypothalamic sympathoexcitatory system in anesthetized animals but not in conscious rats.