Human endothelin receptors characterized using reverse transcriptase-polymerase chain reaction, in situ hybridization, and subtype-selective ligands BQ123 and BQ3020: evidence for expression of ETB receptors in human vascular smooth muscle.

摘要: Our aim was to characterize and determine the function of endothelin (ET) receptor subtypes in human vascular tissue. Reverse transcriptase-polymerase chain reaction with nested oligonucleotide primers detected presence mRNA encoding both ETA ETB receptors media from aorta pulmonary coronary arteries. In situ hybridization confirmed for Saturation binding assays using 125I-ET-1 found a single population high-affinity ET (n = three patients, +/- SEM) (Kd 0.507 0.020 nM; Bmax 9 4 fmol/mg protein) 0.845 0.245 15 10 arteries 0.141 71 21 protein). Using arteries, ETA-selective ligand BQ123 (cyclo[D-Asp-L-Pro-D-Val-L-Leu-D-Trp]) ETB-selective BQ3020 (Ala11,15-Ac-ET-1[6-21]) produced biphasic competition curves against 125I-ET-1, confirming high- low-affinity sites corresponding two subtypes: (KdETA 0.85 0.03 KdETB 7.58 2.27 microM; ETA/ETB, 87%:13%) 0.22 0.04 0.77 0.34 62%:38%). (0.1 microM) caused significant parallel rightward shift ET-1-induced vasoconstriction vitro, but Ala1,3,11,15-ET-1 failed show any agonist activity when tested at concentrations < or 3 microM vessels.(ABSTRACT TRUNCATED AT 250 WORDS)