Sasaki S, Lee L C, Iyota I, Kambara S, Okajima H, Inoue A, Takahashi H, Takeda K, Yoshimura M, Nakagawa M
J Hypertens Suppl. 1986 Oct;4(3):S171-4.
When GABA (4-amino-n-butyric acid, 50-200 micrograms) was injected into the lateral ventricle of urethane-anaesthetized Wistar rats, sympathetic nerve activity, arterial pressure and heart rate were decreased dose-dependently. Graded electrical stimulation of the ventromedial hypothalamus (50, 100 and 150 microA) increased not only mean blood pressure but also the rate of sympathetic nerve firing, and both responses were attenuated by GABA pretreatment (100 and 200 micrograms, i.c.v.). In spontaneously hypertensive rats (SHR), i.c.v.-injected GABA also reduced sympatho-cardiovascular activity, but the magnitude of the depressor responses was significantly larger in SHR than in normotensive Wistar-Kyoto (WKY) control rats. Pressor and sympathetic nerve responses elicited by hypothalamic stimulation were initially larger in SHR than in WKY rats. However, upon subsequent i.c.v. injection of GABA, hypothalamic responsiveness in SHR was inhibited more prominently and became almost the same as that in WKY rats. These results suggest that, by depressing hypothalamic function, central GABA-ergic stimulation decreases sympathetic nerve activity thereby lowering blood pressure and heart rate. Because of the increased central sensitivity in SHR, GABA-ergic stimulation reversed hypothalamo-sympathetic hyperactivity and attenuated hypertension.
当将γ-氨基丁酸（4-氨基-n-丁酸，50 - 200微克）注入氨基甲酸乙酯麻醉的Wistar大鼠侧脑室时，交感神经活动、动脉血压和心率呈剂量依赖性降低。对腹内侧下丘脑进行分级电刺激（50、100和150微安）不仅会提高平均血压，还会增加交感神经放电频率，而这两种反应都会被γ-氨基丁酸预处理（100和200微克，脑室内注射）减弱。在自发性高血压大鼠（SHR）中，脑室内注射γ-氨基丁酸也会降低交感心血管活动，但SHR的降压反应幅度明显大于正常血压的Wistar-Kyoto（WKY）对照大鼠。下丘脑刺激引起的升压和交感神经反应最初在SHR中比在WKY大鼠中更大。然而，随后脑室内注射γ-氨基丁酸后，SHR的下丘脑反应性受到更显著的抑制，几乎与WKY大鼠相同。这些结果表明，通过抑制下丘脑功能，中枢γ-氨基丁酸能刺激降低交感神经活动，从而降低血压和心率。由于SHR中枢敏感性增加，γ-氨基丁酸能刺激逆转了下丘脑-交感神经活动亢进并减轻了高血压。
