Endothelin receptor subtype and physiology of vascular smooth muscle and endothelium

人们普遍认为，内皮素A受体(ET_A)在血管内皮细胞中含量较高，该受体亚型的激活有助于血管收缩。另一方面，ET_B分布于内皮细胞，这些受体参与NO或前列环素的产生。在本研究中，我们首次通过使用选择性内皮素阻滞剂将ET_B细分为ET_1、B1和Gt；此外，还发现ET_AS还细分为ET_&lt；A1&gt；和ET_&lt；A2&gt；我们还发现，内皮素选择性地作用于EA_A受体，使兔主动脉瓣内皮细胞[Ca~(2+)]_i升高。上述结果可能有助于了解内皮素的生理和病理生理作用。

It is generally accepted that endothelin A receptors (ET_A) are more abundant in smooth muscle and the activation of this receptor subtype contributes to smooth muscle contraction. On the other hand ET_Bs are distributed in endothelial cells and these receptors contribute to the production of NO or prostacyclin. We first demonstrated in this study that ET_B is subdivided into ET_<B1> and ET_<B2> by using selective endothelin blockers. Further, it was found that ET_As are also subdivided into ET_<A1> and ET_<A2>. We also found that endothelins act selectively on the EA_A receptor to increase[Ca^<2+>]_i in the endothelium of rabbit aortic valve. The above findings may contribute to the understanding of physiological and pathophysiological role of endothelin.