Characterization of the Endothelin Receptor in Primary Cultures of Human Aortic Smooth Muscle Cells

The Japanese Journal of Pharmacology

Yumiko Honma¹  Hidenori Yazawa¹  Kazuo Honda¹  Emi Iida-Kubota¹ 

[1] Drug Serendipity Research Laboratories, Institute for Drug Discovery Research, Yamanouchi Pharmaceutical Co., Ltd.

关键词: Endothelin;    Receptor;    Aorta (human);    Smooth muscle cell;   

DOI  :  10.1254/jjp.63.313

学科分类：药理学

来源: Nihon Yakuri Gakkai Henshuubu / Japanese Pharmacological Society

【 摘 要 】

References(29)Cited-By(5)We characterized the endothelin receptor subtypes in primary cultures of human aortic smooth muscle cells (HASMCs) by binding studies. [125I]-Endothelin (ET)-1 saturation experiments showed the existence of a homogeneous population of binding sites with the high affinity (KD value) of 97±37 pM and maximum number of binding sites (Bmax) of 54±10 fmol/mg protein. However, almost no specific [125I]-ET-3 binding was observed. Inhibition of [125I]-ET-1 binding in the HASMCs membrane by nonlabelled compounds showed the following order of effectiveness: ET-1=ET-2=FR139317>ET-3. These results suggest that the endothelin receptor of HASMCs is of the ETA type. We also studied the effect of ET-1 on the cytosolic [Ca2+]i in HASMCs loaded with fura-2/AM. In 1.3 mM Ca2+, ET-1 produced a dose-dependent, biphasic increase in signal with a maximal effect at 10 nM. At this concentration, ET-1 produced a transient increase in [Ca 21]i that reached a peak at 1 min, which was followed by a slow but sustained increase in [Ca2+]i. This second phase was attenuated in Ca2+-deficient medium. Furthermore, ET-1 increased inositol 1, 4, 5-triphosphate in a time and dose-dependent manner. These results suggest that the endothelin receptors of HASMCs are of the ETA type, which couple with Ca2+ channels.

【 授权许可】

Unknown