Restricted Propagation of Cytoplasmic Ca2+ Oscillation into the Nucleus in Guinea Pig Cardiac Myocytes as Revealed by Rapid Scanning Confocal Microscopy and Indo-1

The Japanese Journal of Pharmacology

Hikaru Tanaka¹  Ryu Nakamura²  Toru Kawanishi³  Yoshimitsu Kato¹  Koki Shigenobu¹ 

[1] Department of Pharmacology, Toho University School of Pharmaceutical Sciences;Microscopes Development Department, Nikon Corporation;Division of Biochemistry and Biologicals, National Institute of Health Sciences

关键词: Confocal microscopy;    Calcium ion;    Indo-1;    Myocardium;    Nucleus;   

DOI  :  10.1254/jjp.70.235

学科分类：药理学

来源: Nihon Yakuri Gakkai Henshuubu / Japanese Pharmacological Society

【 摘 要 】

References(36)Cited-By(15)Two-dimensional images of cytoplasmic and nuclear free Ca2+ movements in cardiac myocytes were obtained at 67-msec intervals using a Ca2+-sensitive fluorescence probe, indo-1, and a rapid scanning confocal laser microscope, Nikon RCM8000. Isolated guinea pig ventricular cells were loaded with indo-1 and stimulated at 0.5 Hz through patch pipettes. On stimulation, nuclear Ca2+ concentration ([Ca2+]) was observed to rise and fall following cytoplasmic [Ca2+] with an obvious delay. Application of isoproterenol significantly increased the peak [Ca2+] on stimulation in both the cytoplasm and nucleus with no substantial change in the basal [Ca2+]; the increase in peak [Ca2+]produced by application of isoproterenol was larger in the cytoplasm than in the nucleus. Under a low [Na+] condition, the basal [Ca2+] was increased from the control values in both the cytoplasm and nucleus; no difference in basal [Ca2+] was observed between the two regions. The increase in peak [Ca2+] by low [Na+] in the cytoplasm was significantly larger than that in the nucleus. When the cells were voltage clamped at 0 mV for 3 sec, no difference in the steady state [Ca2+] was observed between the cytoplasm and nucleus. Nuclear [Ca2+] was also observed to increase following a Ca2+ wave, a local increase in [Ca2+] propagating within the cytoplasm, with a delay. Thus, we demonstrated in isolated myocardial cells that cytoplasmic Ca2+ movements, although hampered by the nuclear envelope, are propagated into the nucleus, a mechanism through which factors affecting cytoplasmic Ca2+ may influence intranuclear events.

【 授权许可】

Unknown