[3H]PN200-110 binding in a fibroblast cell line transformed with the alpha 1 subunit of the skeletal muscle L-type Ca2+ channel.
We examined the binding of the 1,4-dihydropyridine (DHP) [3H]PN200-110 to membranes from a fibroblast cell line transfected with the alpha 1 subunit (DHP receptor) of the L-type Ca2+ channel from rabbit skeletal muscle. Binding site affinity (KD) and density (Bmax) were 1.16 +/- 0.31 nM and 142 +/- 17 fmoles/mg protein, respectively. This affinity corresponded closely with that observed in native skeletal muscle. The Ca2+ channel antagonists diltiazem and MDL 12,330A stimulated [3H]PN200-110 binding in a dose-dependent manner while flunarizine, quinacrine and trifluoperazine inhibited binding. Surprisingly, D600 also stimulated [3H]PN200-110 binding in a dose-dependent and stereoselective manner. It is concluded that the fibroblast cells used in this study provide a unique system for interactions of the Ca2+ channel ligands with the alpha 1 subunit of the skeletal muscle L-type Ca2+ channel.
Rampe
D
D
Merrell Dow Research Institute, Cincinnati, Ohio 45215.
Kim
H S
HS
Lacerda
A E
AE
Birnbaumer
L
L
Brown
A M
AM
D000818:Animals; D001921:Brain / Q000378:metabolism; D015220:Calcium Channels / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D003001:Cloning, Molecular; D004110:Diltiazem / Q000494:pharmacology; D005711:Gallopamil / Q000494:pharmacology; D007097:Imines / Q000494:pharmacology; D017275:Isradipine; D007739:L Cells; D046911:Macromolecular Substances; D051379:Mice; D009132:Muscles / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism; D010069:Oxadiazoles / Q000378:metabolism*; D011978:Receptors, Nicotinic / Q000235:genetics / Q000378:metabolism*; D012508:Sarcolemma / Q000378:metabolism; D014162:Transfection
D015220:Calcium Channels; D007097:Imines; D046911:Macromolecular Substances; D010069:Oxadiazoles; D011978:Receptors, Nicotinic; D005711:Gallopamil; C014925:RMI 12330A; D004110:Diltiazem; D017275:Isradipine