Nuclear calcium oscillation in cultured neonatal rat myocytes
- VernacularTitle:大鼠心肌细胞胞浆和核Ca~(2+)震荡现象及其机制探讨
- Author:
Jian LIU
;
Zuoyun HE
;
Yingbin XIAO
;
Junfei YIN
;
Peiyon WANG
- Publication Type:Journal Article
- Keywords:
Calcium;
Myocardium;
Norepinephrine;
Isoproterenol
- From:
Chinese Journal of Pathophysiology
2000;0(08):-
- CountryChina
- Language:Chinese
-
Abstract:
AIM: To determine whether nuclear Ca 2+ is independently regulated from the cytosolic Ca 2+ and nuclear Ca 2+ oscillation induced by many modulating factors in cultured rat neonatal myocytes and its mechanism. METHODS: Rat neonatal cardiac myocytes were cultured, and fluo-4/AM was loaded as calcium probe. The changes of cytosolic and nuclear Ca 2+ were observed by confocal laser microscopy. RESULTS: Calcium fluorescent intensity oscillated slightly in myocardiocytes and the average intensity was much higher in the nucleus than that in the cytosole. Ca 2+ oscillation in nucleus and cytosole induced by norepinephrine, isoproperenol, ATP were completely blocked by Ca 2+ -ATPase antagonist thapsigargin (10 -6 mol/L),L-type Ca 2+ channel blocker verapermil (500 ?mol/L) and KCl (20 mmol/L). Ca 2+ -ATPase antagonist thapsigargin completely blocked the propagation of Ca 2+ waves and simutaneouly induced a temporary Ca 2+ increase followed by a magnificient drop and loss of response to norepinephrine. CONCLUSIONS: The results suggested that generation and maintenance of calcium oscillation both in cytosole and nucleus depended on extracellular Ca 2+ influx, membrane potential, Ca 2+ release and uptake of cytosolic and nuclear calcium stores. The difference between cytosolic calcium and nuclear calcium indicated that calcium regulating system relatively independent of cytosole may exist in nucleus.
