Beta-adrenergic receptor binding characteristics and responsiveness in cultured Wistar-Kyoto rat arterial smooth muscle cells.
The tone of arterial blood vessels is regulated by the catecholamines through their receptors on arterial smooth muscle cells (ASMC). beta 2-adrenergic receptors of ASMC mediate vasodilation through agonist mediated c-AMP production. Previous reports have described these receptors on freshly isolated blood vessels. This study demonstrates the presence of beta 2-adrenergic receptors on cultured rat ASMC and that these receptors are functional. beta-adrenergic receptor binding was measured using [3H]-dihydroalprenolol (DHA) binding to the membrane of cultured ASMC from normotensive Wistar-Kyoto rats. The ASMC beta-adrenergic receptors have a Kd of 0.56 +/- 0.16 nM and a Bmax of 57.2 +/- 21.7 fmol/mg protein. Competition binding studies revealed a much greater affinity of these receptors for epinephrine than norepinephrine, indicating the preponderance of a beta 2-adrenergic receptor subtype. Isoproterenol stimulation of cultured ASMC resulted in a 14 +/- 7 fold increase in intracellular c-AMP content of these cells indicating these receptors are functional. beta-adrenergic receptors of cultured ASMC provide an excellent system in which the association between hypertension and observed beta-adrenergic receptor differences can be further explored.
Jazayeri
A
A
University of Texas Medical Branch, Department of Human Biological Chemistry & Genetics, Galveston 77550.
Meyer
W J
WJ
D000818:Animals; D001667:Binding, Competitive; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000096:biosynthesis; D004082:Dihydroalprenolol / Q000378:metabolism; D007545:Isoproterenol / Q000494:pharmacology; D007700:Kinetics; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D051381:Rats; D011921:Rats, Inbred WKY; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*
D011943:Receptors, Adrenergic, beta; D004082:Dihydroalprenolol; D000242:Cyclic AMP; D007545:Isoproterenol