Regulative effects of temperature, intracellular sodium, ATP and pH on I(Na/Ca) of cardiac myocytes / 生理学报
Acta Physiologica Sinica
; (6): 136-140, 2006.
Article
em Zh
| WPRIM
| ID: wpr-265474
Biblioteca responsável:
WPRO
ABSTRACT
The Na(+)-Ca(2+) exchange is a major pathway for removal of cytosolic Ca(2+) in cardiac myocytes. To explore the effects of temperature, intracellular Na(+), ATP and pH on Na(+)-Ca(2+) exchange currents (I(Na/Ca)) of intact guinea-pig myocytes, the whole-cell patch-clamp technique was used to record I(Na/Ca) in isolated guinea-pig ventricular myocytes. We found that I(Na/Ca) at 34 degrees C was four times higher than that at 22 degrees C. However, intracellular acidification had no obvious influence on bidirectional I(Na/Ca). At 22~24 degrees C , intracellular ATP depletion and intracellular acidification did not markedly affect bidirectional I(Na/Ca) either. At 34~37 degrees C , intracellular ATP depletion and intracellular acidification synergistically inhibited the outward and inward currents of I(Na/Ca), and blocked the inward currents of I(Na/Ca)more potently than the outward currents of I(Na/Ca). The effect of ATP on I(Na/Ca) is temperature-dependent. Intracellular higher sodium increased the outward currents of I(Na/Ca) however it did not increase, even sometimes decreased the inward currents of I(Na/Ca). These results suggest that intracellular ATP depletion and intracellular acidification synergistically impair Ca(2+) extrusion via forward mode Na(+)-Ca(2+) exchange, and intracellular sodium overload increases Ca(2+) influx via reverse mode Na(+)-Ca(2+) exchange, leading to calcium overload respectively.
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Índice:
WPRIM
Assunto principal:
Patologia
/
Fisiologia
/
Sódio
/
Temperatura
/
Trifosfato de Adenosina
/
Cálcio
/
Técnicas de Patch-Clamp
/
Trocador de Sódio e Cálcio
/
Biologia Celular
/
Miócitos Cardíacos
Limite:
Animals
Idioma:
Zh
Revista:
Acta Physiologica Sinica
Ano de publicação:
2006
Tipo de documento:
Article