[Age-related changes in transient outward potassium current of rat ventricular myocyte.] [Article in Chinese]
FU Yi-Cheng, CHEN Rui, Chen Mei-Yan, WANG Yan- Li, XU Bin, YANG Jie, YIN Tong, LI Yang
Institute of Geriatric Cardiology, the PLA General Hospital, Beijing 100853, China.
Abstract
The study aimed to investigate the age-related changes and drug reactions of transient outward potassium current (I(to)) of ventricular myocytes. Twenty-eight Sprague Dawley rats were divided into young (3-5 months), adult (13-15 months) and aged (22-24 months) groups, and I(to) currents of isolated myocytes from each group were recorded respectively by patch-clamp. The perfusion of 2.0 mmol/L 4-AP or 1.0 μmol/L isoproterenol was added respectively in each group, and the changes of I(to) were observed. In comparison with young and adult groups, I(to) densities of ventricular myocytes in aged group was significantly increased, the curve of steady-state activation of I(to) shifted to the left, the close-state inactivation rate significantly decreased, and recovery rate from the steady-state inactivation became quicker. However, no significant changes could be detected for the I(to) steady-state inactivation of ventricular myocytes in aged group. The similar responsiveness to 4-AP was observed in all three groups, but the responsiveness to isoproterenol was weaker in the aged group (55.9%) than in the other two groups (127.5% and 125.8%). In conclusion, the results show that I(to) of rat ventricular myocyte of aging heart has increased current density and decreased response to isoproterenol.
Key words: Rats; ventricular myocytes; transient outward potassium current; arrhythmia; patch clamp
Received: 2012-08-17 Accepted: 2013-03-04
Corresponding author: 李泱 E-mail: liyangbsh@163.com
Citing This Article:
FU Yi-Cheng, CHEN Rui, Chen Mei-Yan, WANG Yan- Li, XU Bin, YANG Jie, YIN Tong, LI Yang. [Age-related changes in transient outward potassium current of rat ventricular myocyte.] [Article in Chinese]. Acta Physiol Sin 2013; 65 (2): 185-192 (in Chinese with English abstract).