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Titolo:
Activation of protein kinase C increases acetylcholine release from frog motor nerves by a direct action on L-type Ca2+ channels and apparently not by depolarisation of the terminal
Autore:
Arenson, MS; Evans, SC;
Indirizzi:
Univ London Queen Mary & Westfield Coll, Sch Med & Dent, Div Biomed Sci, Mol Pharmacol Sect, London E1 4NS, England Univ London Queen Mary & Westfield Coll London England E1 4NS S, England
Titolo Testata:
NEUROSCIENCE
fascicolo: 4, volume: 104, anno: 2001,
pagine: 1157 - 1164
SICI:
0306-4522(2001)104:4<1157:AOPKCI>2.0.ZU;2-E
Fonte:
ISI
Lingua:
ENG
Soggetto:
INHIBITOR OKADAIC ACID; PHORBOL ESTERS; TRANSMITTER RELEASE; CALCIUM CHANNELS; SYNAPTIC TRANSMISSION; SENSORY NEURONS; NEUROMUSCULAR-JUNCTION; RAT HIPPOCAMPUS; IN-VITRO; CURRENTS;
Keywords:
neurotransmitter release; endplate current; phorbol ester; protein kinase C inhibitor; L-type calcium channel; neuromuscular junction;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
48
Recensione:
Indirizzi per estratti:
Indirizzo: Arenson, MS Univ London Queen Mary & Westfield Coll, Sch Med & Dent, Div Biomed Sci, Mol Pharmacol Sect, Mile End Rd, London E1 4NS, England Univ London Queen Mary & Westfield Coll Mile End Rd London England E1 4NS
Citazione:
M.S. Arenson e S.C. Evans, "Activation of protein kinase C increases acetylcholine release from frog motor nerves by a direct action on L-type Ca2+ channels and apparently not by depolarisation of the terminal", NEUROSCIENC, 104(4), 2001, pp. 1157-1164

Abstract

The effects of the dihydropyridine Ca2+ channel antagonist nimodipine and the protein kinase C inhibitors staurosporine and calphostin C on the changes in the electrophysiological indices of quantal acetylcholine release induced by a 4-beta -phorbol ester were studied at the frog neuromuscular junction. 4-beta -Phorbol 12-myristate 13-acetate (200 nM) caused an increase in the frequency of miniature endplate potentials and miniature endplate currents and in the quantal content of endplate potentials and endplate currents, These effects were not replicated by 4-alpha -phorbol 12.13-didecanoate(200 nM), Nimodipine (1 muM) itself had no effect on the frequency of miniature endplate potentials and miniature endplate currents and it had no effect on the quantal content. Nimodipine inhibited by 83-98%, the increase inthese parameters induced by 4-beta -phorbol 12-myristate 13-acetate. The increase in the frequency of miniature endplate potentials and currents caused by KCl (12 mM) matched the increase caused by 20 min exposure to 4-beta -phorbol 12-myristate 13-acetate. Nimodipine did not reduce the increase infrequency caused by KCl. Unlike 4-beta -phorbol 12-myristate 13-acetate, KCI (12 mM) prevented neuromuscular transmission. The effects of prior exposure of muscles to staurosporine (5 muM) on 4-beta -phorbol 12-myristate 13-acetate-induced increases in quantal acetylcholine release were inconsistent. In some pretreated fibres, 4-beta -phorbol 12-myristate 13-acetate caused increases in miniature endplate potential frequency and quantal content which were as great as the largest values encountered in fibres that had not been pretreated. In others. 4-beta -phorbol 12-myristate 13-acetate did not have a marked effect: the frequency of the spontaneous potentials and the quantal content of endplate potentials recordedin the presence of 4-beta -phorbol 12-myristate 13-acetate were sometimes less than their respective control values. Pretreatment with calphostin C (500 nM) was more consistent it prevented by 93-100% the 4-beta -phorbol 12-myristate 13-acetate-induced increases in the frequency of miniature endplate potentials and quantal content. Overall, from these results we suggest that activation of protein kinase Cincreases quantal acetylcholine release by opening quiescent L-type Ca2+ channels in motor nerve terminals at resting potential and apparently not bydepolarisation. (C) 2001 IBRO. Published by Elsevier Science Ltd. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 20/01/20 alle ore 10:48:25