Deng L Y, Li J S, Schiffrin E L
MRC Multidisciplinary Research Group on Hypertension, Clinical Research Institute of Montreal, Quebec, Canada.
Cardiovasc Res. 1995 Apr;29(4):532-5.
Endothelins bind to different receptor subtypes identified as ETA and ETB receptors, ETA receptors are present on smooth muscle cells of blood vessels. ETB receptors seem to predominate on endothelial cells of blood vessels, but may also be present on smooth muscle in some vascular beds. The aim of this study was to investigate the distribution of ETA and ETB receptors in human and in rat resistance arteries.
Contractile responses to endothelin-1 and to the ETB agonist sarafotoxin S6c were investigated in human subcutaneous resistance arteries and in rat mesenteric resistance arteries mounted on a wire myograph.
Contractile responses to endothelin-1 were significantly reduced by the ETA selective antagonists BQ123 or BQ610 in human resistance arteries, and were almost abolished by the antagonists in rat arteries. The ETB agonist sarafotoxin S6c induced smaller responses than endothelin-1. When responses to sarafotoxin S6c were obtained in the presence of BQ610, the relatively small contractile response remained. It was slightly enhanced if the responses were obtained in the presence of the nitric oxide synthase inhibitor L-NAME or after removal of the endothelium.
Vasoconstrictor ETB receptors appear to be present in resistance vessels isolated from subcutaneous fat in humans and from the mesentery in rats, but their contribution to endothelin mediated constriction is small, particularly in rat resistance arteries. ETA receptors appear to be the more important endothelin receptor subtype in the human and rat resistance arteries examined.
内皮素可与已确定为ETA和ETB受体的不同受体亚型结合，ETA受体存在于血管平滑肌细胞上。ETB受体似乎在血管内皮细胞上占主导地位，但在某些血管床的平滑肌中也可能存在。本研究的目的是调查ETA和ETB受体在人和大鼠阻力动脉中的分布。
在安装于线肌动描记器上的人皮下阻力动脉和大鼠肠系膜阻力动脉中，研究对内皮素-1和ETB激动剂沙拉新S6c的收缩反应。
在人阻力动脉中，ETA选择性拮抗剂BQ123或BQ610可显著降低对内皮素-1的收缩反应，在大鼠动脉中，该拮抗剂几乎可消除该反应。ETB激动剂沙拉新S6c诱导的反应比内皮素-1小。当在BQ610存在的情况下获得对沙拉新S6c的反应时，相对较小的收缩反应仍然存在。如果在一氧化氮合酶抑制剂L-NAME存在的情况下或去除内皮后获得反应，则该反应会略有增强。
血管收缩性ETB受体似乎存在于从人皮下脂肪分离的阻力血管和从大鼠肠系膜分离的阻力血管中，但它们对内皮素介导的收缩作用较小，尤其是在大鼠阻力动脉中。在检测的人和大鼠阻力动脉中，ETA受体似乎是更重要的内皮素受体亚型。
