The effects of calcium channel agonists and antagonists on the release of endogenous glutamate from cerebellar slices.
The effects of compounds acting at the calcium channel on neurotransmitter release are equivocal. We report here the effects of the antagonists, verapamil, diltiazem and nifedipine; the agonists, bay K8644 and the calcium ionophore, A23187 on the release of endogenous glutamate from rat cerebellar slices. Of these compounds, only verapamil and diltiazem modified glutamate release and these were effective at relatively high concentrations (greater than 1 x 10(-5) M). It is suggested that the high-affinity binding sites found in neuronal tissue for the dihydropyridine-like compounds are not involved in neurotransmitter release.
Barnes
S
S
Department of Pharmacology and Theurapeutics, University of Wales College of Medicine, Cardiff, U.K.
Davies
J A
JA
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology; D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism*; D002531:Cerebellum / Q000187:drug effects / Q000378:metabolism*; D004110:Diltiazem / Q000494:pharmacology; D005260:Female; D005971:Glutamates / Q000378:metabolism*; D018698:Glutamic Acid; D066298:In Vitro Techniques; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D014700:Verapamil / Q000494:pharmacology
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D005971:Glutamates; D000001:Calcimycin; D018698:Glutamic Acid; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D014700:Verapamil; D004110:Diltiazem; D011188:Potassium