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EFFECTS OF HIGH SALT-LOADING ON THE REGULATION OF ANGIOTENSIN II RECEPTOR mRNA EXPRESSION

SUN JU-ZHONG, HAN BO, LIU DONG-QING, DING JIN-FENG, CHANG CHI

(Cardiovascularr Institute mud Fuwai Heart Hospital, ； Chinese Academy of Medical.9ciences, Peking Union Medical College，Beijing 100037)

Abstract

In the present study，the angiotensin 11 receptor subtype I一a (ATla) and I一b(AT 1b)mRNA levels in aortic smooth muscle(ASM)，ventricular myocardium
(VM) and adrenal from 12一week一old stroke-prone spontaneously hypertensive rats (SHRsp) and age-matched Wistar-Kyoto (WKY) rats with normal diet (control) and high salt-loading were examined by reverse transcriptase- polymerase chain reaction (RT-PCR).The results showed that:(1)The AT] a and ATlb mRNA levels in ASM and VM from SHRsp were lower than those from WKY rats(in ASM，10%and 23%，while in VM，23%and 4 0%lower，respectively).In contrast，both AT la and AT] b mRNA levels in adrenal from SHRsp were higher(176%and 157%，respective1y).(2)In the WKY rats with high salt-loading，the AT Ia and AT 1b mRNA levels in adrenal，as well as AT]b mRNA level in VM，increased significantly，as compared with the control (in adrenal，167%and 401%，while in VM，62%}.However，the AT 1 a and AT I b mRNA levels in ASM，as well as AT] a mRNA level in VM，showed no obvious change.(3)In SHRsp with high salt-loading，the AT] b mRNA level in ASM，as well as AT l a and AT l b mRNA levels in VM，increased markedly (in ASM， 90%，while in VM，590%and 200%);whereas the AT 1 a mRNA level in adrenal decreased significantly(58%).There was little influence on the regulation of AT l a (in ASM)and ATIb (in adrenal)receptor gene expression after high salt-loading. The results suggest that AT l a and AT 1 b receptors may be involved in the pathogenesis of saltinduced hypertension. The up-regulation of AT l b receptors in ASM may induce the re
modeling of arterial wall，while that of AT la and AT 1b receptors in VM might contribute to ventricular hypertrophy in hypertension. Furthermore，there are certain differences between SHRsp and WKY rats with respect to the regulation of ATIa and AT I b receptor gene expression with or without external stimulation.

Key words: high salt-loading;stroke-prone spontaneously hypertensive rats;angiotensin receptor;

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Citing This Article：

SUN JU-ZHONG, HAN BO, LIU DONG-QING, DING JIN-FENG, CHANG CHI. EFFECTS OF HIGH SALT-LOADING ON THE REGULATION OF ANGIOTENSIN II RECEPTOR mRNA EXPRESSION. Acta Physiol Sin 1996; 48 (4): (in Chinese with English abstract).