[3H]ouabain binding to cultured rat vascular smooth muscle cells.
The number of Na+ pump units (Bmax) and the equilibrium dissociation constant (Kd) for ouabain as well as parameters of K+ binding to the Na+ pump were examined in in vitro-grown vascular smooth muscle cells ( VSMC ) derived from Sprague-Dawley rats. The technique to measure these variables utilizes analyses of [3H]ouabain displacement from its VSMC receptors by nonlabeled ouabain and K+. The mean values for Bmax and Kd in the cultured VSMCs were 1.95 X 10(5) receptor sites per single VSMC and 2.68 X 10(-6) M, respectively. The equilibrium dissociation constant for K+ (Ki) was 0.92 mM. K+ binding to the cultured VSMCs demonstrated positive cooperativity with a Hill coefficient (n) of 1.78.
D000818:Animals; D001667:Binding, Competitive; D002339:Carotid Arteries / Q000378:metabolism*; D002478:Cells, Cultured; D007700:Kinetics; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D010042:Ouabain / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D011955:Receptors, Drug / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
D011955:Receptors, Drug; C028996:cardiac glycoside receptors; D010042:Ouabain; D000254:Sodium-Potassium-Exchanging ATPase