自发性高血压大鼠中枢血管紧张素Ⅱ的变化对中枢肾上腺素和去甲肾上腺素含量的影响

EFFECT OF THE OVERACTIVATED CENTRAL RENINANGIOTENSIN SYSTEM ON THE CONCENTRATION OF BRAIN NOREPINEPHRINE AND EPINEPHRINE IN STROKE-PRONE SPONTANEOUSLY HYPERTENSIVE RATS AND ITS SIGNIFCANCES

自发性高血压大鼠中枢肾上腺能递质含量异常,然其原因仍不清楚。本工作发现:12周龄易卒中型自发性高血压大鼠(SHRSP)脑桥,下丘脑后部、尾核中去甲肾上腺素(NE)含量及延髓、下丘脑前部,下丘脑后部中肾上腺素(E)含量均高于同龄 Wista Kyoto 大鼠(WKY),SHRSP 中枢 AⅡ含量亦明显高于同龄 WKY;向8周龄 SHRSP 和 WKY 侧脑室慢性灌注巯甲丙脯氨酸,不仅降低动脉血压及各脑区AⅡ含量,亦使中枢 NE 及 E 水平下降,但巯甲丙脯氨酸对 SHRSP 的影响远较对 WKY 明显。结果提示:SHRSP 中枢肾上腺能递质含量增加可能与 SHRSP 中枢 AⅡ量含量升高以及 SHRSP 中枢 AⅡ对中枢肾上腺能递质的促释放调节机制明显易化有关。

The content of norepinephrine(NE)and epinephrine(E)in the brain ofspontaneously hypertensive rats has proved abnormal,but the cause remainedunknown.It was shown in the recent work that NE content in pons,posterior hy-pothalamus,nucleus caudatus and E concentration in medulla oblongata,anter-ior and posterior hypothalamus of 12-week old stroke-prone spontaneously hy-pertensive rats(SHRSP)were much higher than those of age-matched Wister-Kyoto rats(WKY).SHRSP also showed higher levels of systolic blood pressure(SBP)and brain angiotensin Ⅱ(AⅡ)than WKY.Intracerebroventricular(icv)perfusion of angiotensin-converting enzyme inhibitor captopril(20μg foreach time and three times for each day for four weeks)inhibited the synthesis ofbrain AⅡand reduced SBP and NE,E contents in all examined brain areas inSHRSP and WKY.However,the effects of chronically perfused captopril onSBP and brain NE,E levels in SHRSP were much more significant than in WKY.The results indicate that the modulatory effects of central renin-angiotensin sys-tem(RAS)on central adrenergic and noradrenergic systems might be over-activated in SHRSP,which might partially responsible for the abnormally highlevels of NE.E in some of the brain areas of SHRSP.