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Titolo:
Functional role of ionic regulation of Na+/Ca2+ exchange assessed in transgenic mouse hearts
Autore:
Maxwell, K; Scott, J; Omelchenko, A; Lukas, A; Lu, LY; Lu, YJ; Hnatowich, M; Philipson, KD; Hryshko, LV;
Indirizzi:
Univ Manitoba, St Boniface Gen Hosp, Res Ctr, Inst Cardiovasc Sci, Winnipeg, MB R2H 2A6, Canada Univ Manitoba Winnipeg MB Canada R2H 2A6 ci, Winnipeg, MB R2H 2A6, Canada Univ Calif Los Angeles, Cardiovasc Res Lab, Los Angeles, CA 90095 USA UnivCalif Los Angeles Los Angeles CA USA 90095 Los Angeles, CA 90095 USA Univ Calif Los Angeles, Dept Physiol, Los Angeles, CA 90095 USA Univ CalifLos Angeles Los Angeles CA USA 90095 Los Angeles, CA 90095 USA Univ Calif Los Angeles, Dept Med, Los Angeles, CA 90095 USA Univ Calif LosAngeles Los Angeles CA USA 90095 Los Angeles, CA 90095 USA
Titolo Testata:
AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY
fascicolo: 6, volume: 277, anno: 1999,
pagine: H2212 - H2221
SICI:
0363-6135(199912)277:6<H2212:FROIRO>2.0.ZU;2-V
Fonte:
ISI
Lingua:
ENG
Soggetto:
CARDIAC NA+-CA2+ EXCHANGER; NA-CA EXCHANGE; SODIUM-CALCIUM EXCHANGE; VENTRICULAR MYOCYTES; SARCOPLASMIC-RETICULUM; DYNAMIC PROPERTIES; TRANSPORT SYSTEMS; STEADY-STATE; MUSCLE; RABBIT;
Keywords:
giant excised patch; sodium-calcium exchange; ionic regulation; postrest potentiation;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
38
Recensione:
Indirizzi per estratti:
Indirizzo: Hryshko, LV Univ Manitoba, St Boniface Gen Hosp, Res Ctr, Inst Cardiovasc Sci, 351 Tache Ave, Winnipeg, MB R2H 2A6, Canada Univ Manitoba 351 Tache Ave Winnipeg MB Canada R2H 2A6 Canada
Citazione:
K. Maxwell et al., "Functional role of ionic regulation of Na+/Ca2+ exchange assessed in transgenic mouse hearts", AM J P-HEAR, 277(6), 1999, pp. H2212-H2221

Abstract

Na+/Ca2+ exchange is the primary mechanism mediating Ca2+ efflux from cardiac myocytes during diastole and, thus, can prominently influence contractile force. In addition to transporting Na+ and Ca2+, the exchanger is also regulated by these ions. Although structure-function studies have identifiedprotein regions of the exchanger subserving these regulatory processes, their physiological importance is unknown. In this study, we examined the electrophysiological and mechanical consequences of cardiospecific overexpression of the canine cardiac exchanger NCX1.1 and a deletion mutant of NCX1.1 (Delta 680-685), devoid of intracellular Na+ (Na-i(+))- and Ca2+ (Ca-i(2+))-dependent regulatory properties, in transgenic mice. Using the giant excised patch-clamp technique, normal ionic regulation was observed in membrane patches from cardiomyocytes isolated from control and transgenic mice overexpressing NCX1.1. In contrast, ionic regulation was nearly abolished in mice overexpressing Delta 680-685, indicating that the native regulatory processes could be overwhelmed by expression of the transgene. To address the physiological consequences of ionic regulation of the Na+/Ca2+ exchanger, we examined postrest force development in papillary muscles from NCX1.1 and Delta 680-685 transgenic mice. Postrest potentiation was found to be substantially greater in Delta 680-685 than in NCX1.1 transgenic mice, supporting the notion that ionic regulation of Na+/Ca2+ exchange plays a significant functional role in cardiac contractile properties.

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Documento generato il 30/10/20 alle ore 23:33:41