title: Solubilization of the calcium antagonist receptor from rat brain.
abstract: [3H]Nitrendipine binds with high affinity to a calcium antagonist receptor in rat brain membranes. At 4 degrees C, treatment with digitonin solubilized the calcium antagonist receptor as a stable complex with [3H]nitrendipine. The nitrendipine concentration that gave a half-maximal amount of the solubilized [3H]nitrendipine-receptor complex was identical to the Kd for specific nitrendipine binding to brain membranes. Nitrendipine dissociated from digitonin-solubilized and membrane-bound receptors with a half-time of 24 to 30 min at 20 degrees C. Verapamil increased and diltiazem decreased the dissociation rate to a similar extent in both preparations indicating that the solubilized receptor contains both the dihydropyridine and diltiazem/verapamil binding sites. Sucrose gradient sedimentation experiments gave a value of S20, omega = 19.2 for the receptor-digitonin complex. The solubilized calcium antagonist receptor binds specifically to wheat germ agglutinin-Sepharose columns consistent with an identification as a glycoprotein.
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000378:metabolism*; D015220:Calcium Channels; D002462:Cell Membrane / Q000378:metabolism; D004072:Digitonin; D007700:Kinetics; D009543:Nifedipine / Q000031:analogs & derivatives / Q000378:metabolism*; D009568:Nitrendipine; D011725:Pyridines / Q000378:metabolism*; D051381:Rats; D011950:Receptors, Cholinergic / Q000378:metabolism*; D011978:Receptors, Nicotinic / Q000378:metabolism*; D012995:Solubility; D013574:Synaptosomes / Q000378:metabolism
chemical_list: D002121:Calcium Channel Blockers; D015220:Calcium Channels; D011725:Pyridines; D011950:Receptors, Cholinergic; D011978:Receptors, Nicotinic; D009568:Nitrendipine; D009543:Nifedipine; D004072:Digitonin