[Study of H(+)-Ca2+ exchange in cultured heart cells after hypoxia and reoxygenation].
Reoxygenation is more serious for hypoxic myocardial cells because of the subsequent calcium overload. The calcium overload is known due to augmentation of H(+)-Na+, Na(+)-Ca2+, exchange during pH paradox. But the present experiment showed that, when H(+)-Na+, Na(+)-Ca2+ exchange was inhibited, calcium could still enter myocardial cells after hypoxia or reoxygenation. Similar result was observed after using Na(+)-Free solution, suggesting that calcium entrance into the cell was unrelated to Na+ channel. It was further shown that calcium accumulation was related to pH gradient across the myocardial cell membrane, i.e., being increased with increase of H+ concentration in the cell. Therefore, it appears that, besides H(+)-Na+, Na(+)-Ca2+ exchange, H(+)-Ca2+ exchange is one of the reasons of calcium overload during intracellular pH paradox.
Zhang
B Q
BQ
Department of Physiology, Hebei Academy of Medical Science, Shijiazhaung.
Ma
N
N
Dong
L
L
Zhou
X Y
XY
Yu
Z J
ZJ
Wu
Y J
YJ
D000818:Animals; D001693:Biological Transport, Active; D002118:Calcium / Q000378:metabolism*; D015687:Cell Hypoxia; D002478:Cells, Cultured; D006863:Hydrogen-Ion Concentration; D017136:Ion Transport; D008297:Male; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D010101:Oxygen Consumption; D051381:Rats; D017207:Rats, Sprague-Dawley; D012964:Sodium / Q000378:metabolism*; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism
D017923:Sodium-Hydrogen Exchangers; D012964:Sodium; D002118:Calcium