肾血管性高血压大鼠脑室注射γ-氨基丁酸的心血管效应(英文)

Cardiovascular responses to intracerebroventricular injection of GABA in renovascular hypertensive rats

GABA(100和200μg,icv)在肾血管性高血压大鼠(RVHR)产生较伪手术鼠更强的降压作用,尤术后4 wk,GABA降压增强的大部分可被预先icv卡托普利所取消,而ip卡托普利作用较弱,GABA icv还明显改善RVHR已下降的压力感受性反射敏感性,提示RVHR脑内GABA抑制功能不足;外源性GABA降压效应增强可能与其抑制脑内血管紧张素系统有关。

Effects of central GABAergic stimulation on cardiovascular function were evaluated in 2-kidney, 1-clip (2K1C) renovas-cular hypertensive rats (RVHR). Intracere-broventricular injection (icv) of GABA (100 and 200 μg) reduced blood pressure (BP) to a greater degree in RVHR as compared with sham-operated controls, and the greatest response was seen in RVHR 4 wk after operation (4 wk-RVHR). In addition, a decreased sensitivity of baroreflex was observed in 4 wk-RVHR , and was improved by icv GABA. Pretreatment with icv captopril (200 μg) only reduced BP moderately in 4 wk-RVHR, but attenuated remarkably the depressor effect of GABA. On the contrary, pretreatment with ip captopril was less effective in attenuating the depressor effect of GABA. Our results indicated that RVHR was deficient in central GABAergic inhibition on BP control, for GABAergic stimulation reduced BP to a greater degree and improves the decreased sensitivity of baroreflex in RVHR) the depressor effect of GABA is mediated, at least in part, by inhibiting brain angiotensin system.