title: Involvement of basal and calcium-activated protein kinase C in neurotransmitter secretion in mouse motor synapses.
abstract: Blocker of presynaptic protein kinase C isoforms, GF109203X, reduced quantal content of single and rhythmic evoked end-plate potentials. The increase in quantal content of single potentials under the effect of 4- aminopyridine was neutralized by 75% under the effect of L-type Ca(2+)-channel blocker nitrendipine and completely returned to the control level after protein kinase C inhibition with chelerythrine. Neither nitrendipine, nor GF109203X affected the potentiating effect of tetraethylammonium on quantal content of end-plate potentials. Thus, we discovered basal activity of presynaptic protein kinase C under normal conditions that is aimed at the maintenance of quantal content of evoked release. It has been concluded that 4-aminipyridine, but not tetraethylammonium, triggers Ca(2+) entry into the terminal, which activates protein kinase C and enhanced the evoked acetylcholine release.
authors.affiliation: Department of Human and Animal Physiology, Biological Faculty, M. V. Lomonosov Moscow State University, Russia. gaydukov@gmail.com
authors.forename: A E
authors.initials: AE
authors.lastname: Gaydukov
authors.forename: A A
authors.initials: AA
authors.lastname: Marchenkova
authors.forename: O P
authors.initials: OP
authors.lastname: Balezina
mesh_terms: D015761:4-Aminopyridine / Q000494:pharmacology; D000818:Animals; D053119:Benzophenanthridines / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020746:Calcium Channels, L-Type; D020013:Calcium Signaling / Q000187:drug effects; D003964:Diaphragm / Q000187:drug effects / Q000502:physiology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D007211:Indoles / Q000494:pharmacology; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000378:metabolism; D008301:Maleimides / Q000494:pharmacology; D051379:Mice; D009045:Motor Endplate / Q000187:drug effects / Q000502:physiology; D018377:Neurotransmitter Agents / Q000378:metabolism*; D009568:Nitrendipine / Q000494:pharmacology; D009924:Organ Culture Techniques; D026902:Potassium Channel Blockers / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D013569:Synapses / Q000187:drug effects* / Q000201:enzymology; D009435:Synaptic Transmission / Q000187:drug effects* / Q000502:physiology; D019789:Tetraethylammonium / Q000494:pharmacology
chemical_list: D053119:Benzophenanthridines; D002121:Calcium Channel Blockers; D020746:Calcium Channels, L-Type; D007211:Indoles; D007527:Isoenzymes; D008301:Maleimides; D018377:Neurotransmitter Agents; D026902:Potassium Channel Blockers; D047428:Protein Kinase Inhibitors; D019789:Tetraethylammonium; D009568:Nitrendipine; D015761:4-Aminopyridine; C016299:chelerythrine; D011493:Protein Kinase C; C070515:bisindolylmaleimide I; D002118:Calcium