Power R F, Wharton J, Zhao Y, Bloom S R, Polak J M
Department of Histochemistry, Hammersmith Hospital, London, England.
J Cardiovasc Pharmacol. 1989;13 Suppl 5:S50-6; discussion S74. doi: 10.1097/00005344-198900135-00013.
Specific high-affinity binding sites for endothelin-1 (ET-1) have been demonstrated in peripheral tissues using the technique of in vitro receptor autoradiography. Binding was time dependent and saturable and inhibited by coincubation with an excess of unlabeled ET-1 but resistant to dissociation. Binding sites were localized to blood vessels of all sizes including coronary arteries, intrapulmonary vessels, and intrarenal and intrasplenic arteries. In addition, high-affinity binding sites were identified on airway smooth muscle, over alveolar septa, and on nerve trunks. Scatchard analysis of the data revealed a Bmax of 250 amol/mm2 and a Kd of 0.1 nM for the binding of rat tracheal smooth muscle, with similar values for porcine coronary artery. The localization of binding sites is consistent with the known effects of ET-1 and suggests a direct action on specific receptors.
利用体外受体放射自显影技术已在外周组织中证实了内皮素 -1（ET-1）的特异性高亲和力结合位点。结合具有时间依赖性和饱和性，与过量未标记的ET-1共同孵育可抑制结合，但对解离具有抗性。结合位点定位于各种大小的血管，包括冠状动脉、肺内血管、肾内动脉和脾内动脉。此外，在气道平滑肌、肺泡隔和神经干上也鉴定出了高亲和力结合位点。对数据进行Scatchard分析显示，大鼠气管平滑肌结合的Bmax为250 amol/mm²，Kd为0.1 nM，猪冠状动脉的数值与之相似。结合位点的定位与ET-1的已知作用一致，提示其对特定受体有直接作用。
