title: [3H] verapamil binding sites in skeletal muscle transverse tubule membranes.
abstract: [3H]verapamil binding to muscle tubule membrane has the following properties. KD = 27 +/- 5 nM and maximum binding capacity Bmax = 50 +/- 5 pmol/mg of protein. A 1 = 1 stoichiometry of binding was found for the ratio of [3H]verapamil versus [3H] nitrendipine binding sites. The dissociation constant found at equilibrium is near that determined from the ratio of the rate constants for association (k1) and dissociation (k-1). Antiarrhythmic drugs like D600, diltiazem and bepridil are competitive inhibitors of [3H] verapamil binding with KD values between 40 and 200 nM. Dihydropyridine analogs are apparent non competitive inhibitors of [3H]verapamil binding with half-maximum inhibition values (K0.5) between 1 and 5 nM.
mesh_terms: D000818:Animals; D001665:Binding Sites; D002121:Calcium Channel Blockers / Q000494:pharmacology; D007425:Intracellular Membranes / Q000378:metabolism*; D007700:Kinetics; D008870:Microtubules / Q000378:metabolism*; D009132:Muscles / Q000378:metabolism*; D011817:Rabbits; D014700:Verapamil / Q000378:metabolism*
chemical_list: D002121:Calcium Channel Blockers; D014700:Verapamil