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Titolo:
REGULATION OF THE GATING OF THE SHEEP CARDIAC SARCOPLASMIC-RETICULUM CA2-RELEASE CHANNEL BY LUMINAL CA2+()
Autore:
SITSAPESAN R; WILLIAMS AJ;
Indirizzi:
NATL HEART & LUNG INST,DEPT CARDIAC MED LONDON SW3 6LY ENGLAND NATL HEART & LUNG INST,DEPT CARDIAC MED LONDON SW3 6LY ENGLAND
Titolo Testata:
The Journal of membrane biology
fascicolo: 3, volume: 137, anno: 1994,
pagine: 215 - 226
SICI:
0022-2631(1994)137:3<215:ROTGOT>2.0.ZU;2-6
Fonte:
ISI
Lingua:
ENG
Soggetto:
CALCIUM-RELEASE CHANNELS; RYANODINE RECEPTOR CHANNEL; SKELETAL-MUSCLE; CHLORIDE CHANNELS; CA-2+ RELEASE; ACTIVATION; CONDUCTION; MODULATION; CAFFEINE;
Keywords:
CA2+-RELEASE CHANNELS; SARCOPLASMIC RETICULUM; CARDIAC; SULMAZOLE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
28
Recensione:
Indirizzi per estratti:
Citazione:
R. Sitsapesan e A.J. Williams, "REGULATION OF THE GATING OF THE SHEEP CARDIAC SARCOPLASMIC-RETICULUM CA2-RELEASE CHANNEL BY LUMINAL CA2+()", The Journal of membrane biology, 137(3), 1994, pp. 215-226

Abstract

We investigated the effects of changes in luminal [Ca2+] on the gating of native and purified sheep cardiac sarcoplasmic reticulum (SR) Ca2-release channels reconstituted into planar phospholipid bilayers. The open probability (P-o) of channels activated solely by cytosolic Ca2 was greater at positive than negative holding potentials. Channels activated solely by 10 mu M cytosolic Ca2+ exhibited no change in steady-state P-o or in the relationship between P-o and voltage when the luminal [Ca2+] was increased from nanomolar to millimolar concentrations. In the absence of activating concentrations of cytosolic Ca2+, the channel can be activated by the phosphodiesterase inhibitor sulmazole (AR-L 115BS). However, cytosolic Ca2+-independent activation of the channel by sulmazole requires luminal Ca2+. In the presence of sulmazole,at picomolar luminal [Ca2+] the channel remains completely closed. Increasing the luminal [Ca2+] to millimolar levels markedly increases the P-o via an increase in the duration of open events. The P-o and duration of the sulmazole-activated, luminal Ca2+-dependent channel openings are voltage dependent. In the presence of micromolar luminal Ca2+, the P-o and duration of sulmazole-activated openings are greater at negative voltages. However, at millimolar luminal [Ca2+], long openings are also observed at positive voltages and the P-o appears to be similar at positive and negative voltages. Our findings indicate that the regulation of channel gating by luminal Ca2+ depends on the mechanism of channel activation.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 09/07/20 alle ore 01:17:28