title: Calcium channel agonists and antagonists regulate protein phosphorylation in intact synaptosomes.
abstract: Protein phosphorylation in intact synaptosomes is highly sensitive to alterations in calcium fluxes and was used to probe the possible mechanism of action of the calcium channel agonist BAY K 8644 and antagonists verapamil and nifedipine. These agents (at 1 microM) all increased the basal phosphorylation of a specific set of 4 synaptosomal phosphoproteins termed P139, P124, P96 and P60, but did not alter depolarization-dependent protein phosphorylation. The increases could not be explained by a direct stimulation of protein kinases and appears unrelated to the known effects of these drugs on K+-stimulated neurotransmitter release. This finding may reveal a possible new mechanism of action for drugs which interact with calcium channels.
mesh_terms: D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000502:physiology*; D003342:Corpus Striatum / Q000378:metabolism; D007473:Ion Channels / Q000502:physiology*; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009543:Nifedipine / Q000031:analogs & derivatives / Q000494:pharmacology; D010758:Phosphorus / Q000494:pharmacology; D010761:Phosphorus Radioisotopes; D010766:Phosphorylation; D013574:Synaptosomes / Q000378:metabolism*; D014700:Verapamil / Q000494:pharmacology
chemical_list: D002121:Calcium Channel Blockers; D007473:Ion Channels; D009419:Nerve Tissue Proteins; D010761:Phosphorus Radioisotopes; D010758:Phosphorus; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D000255:Adenosine Triphosphate; D014700:Verapamil; D009543:Nifedipine; D002118:Calcium