The coupling responses of α_1 -adrenoreceptors of rat cardiac myocytes

The α_1 -adrenoceptor and its coupled responses were studied in rat isolated cardiac ventricular myocytes. The binding experiment using hydrophylic α_1 -antagonist ^^3 H-bunazosin, with intact myocytes showed the existence of the receptors on the cell surface. α_1 -receptor stlmulatlon resulted in a...

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Bibliographic Details
Published in:Japanese Journal of Pharmacology 1988, Vol.46 (suppl), p.202-202
Main Authors: Yasuhiro Watanabe, Yoshiko Matsumori, Katsuomi Iwakura, Nobuo Sakagoshi, Naoyuki Misaki, Eitetsu Boku, Hideo Kawamoto, Taro Imaizumi, Hiroshi Yoshida
Format: Article
Language:Japanese
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Summary:The α_1 -adrenoceptor and its coupled responses were studied in rat isolated cardiac ventricular myocytes. The binding experiment using hydrophylic α_1 -antagonist ^^3 H-bunazosin, with intact myocytes showed the existence of the receptors on the cell surface. α_1 -receptor stlmulatlon resulted in an accumulatlon of ^^3 H-inositol phosphates in ^^3 H-inositol-labelled cells and ^^3 H-arachidonic acid release in ^^3 H-arachidonic acid-labelled cells, respectively. ^^3 H-Arachidonic acid release by α_1 -stimulation was inhibited by islet-activation protein (IAP) treatment. Finally, ADP-ribosylation of 41 K by IAP was observed in isolated cardiac myocytes. These suggested the α_1 -receptors of the cells coupled with phospholipase C and A_2 , and the latter coupling was mediated through IAP-sensitive GTP-binding protein. And the increase of cGMP and 「Ca^2+ 」_i of α_1 -stimulation was not detected in the experimental condition.
ISSN:0021-5198