Absence of a direct coupling of a G protein to dihydropyridine binding sites in rat heart.
In rat heart membranes, the addition of guanine 5'-O-(3-thiotriphosphate) (GTP-gamma-S), a stable GTP analogue, did not significantly modify the displacement of [3H]PN 200-110 binding by the 1,4-dihydropyridine (DHP) agonist Bay K 8644 and antagonists, nifedipine and nicardipine. These results are in agreement with some previously reported electrophysiological and pharmacological data, and they suggest that there is no direct involvement of a G protein in the modulation of DHP sensitive Ca channels in cardiac cells.
Huguet
F
F
INSERM U 316, Faculté de Médecine, Tours et Institut des Xénobiotiques, Poitiers, France.
Brisac
A M
AM
Roche
A
A
Dubray
C
C
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D015220:Calcium Channels / Q000378:metabolism*; D004095:Dihydropyridines / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006321:Heart / Q000187:drug effects; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D009529:Nicardipine / Q000378:metabolism; D009543:Nifedipine / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D015220:Calcium Channels; D004095:Dihydropyridines; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D009529:Nicardipine; D019204:GTP-Binding Proteins; D009543:Nifedipine