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Differnt susceptibilities to desensitization of three #alpha#_(1)-adrenoceptor subtypes induced by sustained norepinephrine stimulation

Zhang Youyi, Tian Bin, Chen Shonghai, Li Yanfang, Han Qide

Institute of Vascular Medicine, Third Hospital, Beijing Medical University. Beijing 100083

Abstract

cDNAs for the bovine #alpha#_(1A)-,hamster #alpha#_(1B)- and rat #alpha#_(1D)-adrenoceptors (AR) were transfected into human embryonic kidney 293 (HEK 293) cells by calcium phosphate precipitation and stably expressed at high levels. The inositol phosphates (InsPs) accumulation was measured by the method of ~(3)H-inositol incorporation and column chromatography. Susceptibilities to the desensitizaton of #alpha#_(1)-AR subtypes-mediated InsPs accumulation were determined in HEK 293 cells stimulated sustainedly by norepinephrine (NE).The NE-induced InsPs accumulation showed progressive decrease by NE pretreatment with increasing time of preincubation and concentration of NEin the cells transfected with all the #alpha#_(1)-AR subtypes. However, susceptibilities to the desensitization were different among the three subtypes. The desensitization of #alpha#_(1A)-AR took place earliest and needed lowest concentration of NE. The desensitization of #alpha#_(1D)-AR appeared to be the latest and needed hightest concentration of NE, while #alpha#_(1B)-AR stood in between.

Key words: #alpha#_1-adrenoceptor;Agonist;Desensitization;Receptor subtypes;Inositol phosphates

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Citing This Article：

Zhang Youyi, Tian Bin, Chen Shonghai, Li Yanfang, Han Qide. Differnt susceptibilities to desensitization of three #alpha#_(1)-adrenoceptor subtypes induced by sustained norepinephrine stimulation. Acta Physiol Sin 1997; 49 (1): (in Chinese with English abstract).