Subtypes of voltage-sensitive calcium channels in cultured rat brain neurons.
Subtypes of voltage-sensitive calcium channels have been investigated in cultured rat brain neurons using two classes of specific probes, dihydropyridine compounds and omega-conotoxin. Membranes prepared from cultured neurons contain specific binding sites for [3H]PN200-110, a dihydropyridine antagonist, and for 125I-omega-conotoxin with a stoichiometry of about 1:1. A depolarization induced 45Ca2+ influx into intact brain neurons was partially inhibited by a dihydropyridine antagonist, nifedipine and stimulated by a dihydropyridine agonist, Bay K8644. This dihydropyridine sensitive 45Ca2+ flux was insensitive to omega-conotoxin at concentrations which saturate the specific toxin binding sites indicating that in cultured brain neurons, dihydropyridine-sensitive calcium channels are not sensitive to omega-conotoxin.
Martin-Moutot
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N
Laboratoire de Biochimie, INSERM U 172, CNRS URA 1179, Faculté de Médecine Nord, Marseilles, France.
Seagar
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M
Couraud
F
F
D000818:Animals; D001921:Brain / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D002118:Calcium / Q000493:pharmacokinetics / Q000502:physiology*; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D017275:Isradipine; D008564:Membrane Potentials / Q000187:drug effects; D010069:Oxadiazoles / Q000494:pharmacology*; D010456:Peptides, Cyclic / Q000494:pharmacology*; D051381:Rats; D020960:omega-Conotoxins
D015220:Calcium Channels; D010069:Oxadiazoles; D010456:Peptides, Cyclic; D020960:omega-Conotoxins; C053423:Conus magus toxin; D002118:Calcium; D017275:Isradipine