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Titolo:
Tonic regulation of excitation-contraction coupling by basal protein kinase C activity in isolated cardiac myocytes
Autore:
Nicolas, JM; Renard-Rooney, DC; Thomas, AP;
Indirizzi:
Thomas Jefferson Univ, Dept Anat Pathol & Cell Biol, Philadelphia, PA 19107 Thomas Jefferson Univ Philadelphia PA USA 19107 l, Philadelphia, PA 19107
Titolo Testata:
JOURNAL OF MOLECULAR AND CELLULAR CARDIOLOGY
fascicolo: 12, volume: 30, anno: 1998,
pagine: 2591 - 2604
SICI:
0022-2828(199812)30:12<2591:TROECB>2.0.ZU;2-G
Fonte:
ISI
Lingua:
ENG
Soggetto:
ACTOMYOSIN MGATPASE ACTIVITY; RAT VENTRICULAR MYOCYTES; PHORBOL ESTER; SARCOPLASMIC-RETICULUM; SINGLE CARDIOMYOCYTES; CYTOSOLIC CA-2+; CA2+ TRANSIENTS; ANGIOTENSIN-II; HEART-CELLS; TROPONIN-I;
Keywords:
cardiomyocytes; protein kinase C; cytosolic calcium; contractility; calcium influx; sarcoplasmic reticulum;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
43
Recensione:
Indirizzi per estratti:
Indirizzo: Thomas, AP Univ85ed & Dent New Jersey, New Jersey Med Sch, Dept Physiol & Pharmacol, 1 Univ Med & Dent New Jersey 185 S Orange Ave Newark NJ USA 07103
Citazione:
J.M. Nicolas et al., "Tonic regulation of excitation-contraction coupling by basal protein kinase C activity in isolated cardiac myocytes", J MOL CEL C, 30(12), 1998, pp. 2591-2604

Abstract

A high-speed imaging technique was used to investigate the effects of inhibitors and activators of protein kinase C (PKC) on the [Ca2+](i), transients and contraction of fura-2 loaded rat Ventricular cardiac myocytes. The amplitude of the [Ca2+](i) transient was reduced following treatment with 100nM phorbol 12,13-dibutyrate (PDBu), whereas the PKC inhibitors staurosporine (0.5 mu M) and calphostin C (10 mu M) increased [Ca2+](i) transient amplitude, elevated basal [Ca2+](i) and slowed the decay of the [Ca2+](i) transient. These changes were paralleled by similar alterations in the rate and extent of cell shortening. The activity of nitrendipine-sensitive Ca2+ channels was monitored indirectly as the rate of Mn2+ quench of cytosolic fura-2 in electrically-paced cells. PDBu reduced Mn2+ influx by six-fold, whereas staurosporine and calphostin C increased the influx rate by eightfold andseven-ford over basal quench, respectively. The caffeine releasable Ca2+ pool was reduced in the presence of PDBu and increased transiently in presence of staurosporine. The effects of PKC activation and inhibition on sarcoplasmic reticulum Ca2+ content may be secondary to alterations of sarcolemmal Ca2+ influx. However, the PKC inhibitors also decreased the rate of sarcoplasmic reticulum Ca2+ uptake in permeabilized myocytes, suggesting that a direct effect of PKC on the sarcoplasmic reticulum may contribute to the prolongation of the [Ca2+](i) transient under these conditions. The present work demonstrates that basal PKC activity has a potent depressant effect, mediated primarily through inhibition of sarcolemmal Ca2+ influx, which may play a key role in setting the basal tone of cardiac muscle. (C) 1998 Academic Press.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 02/07/20 alle ore 22:06:54