Korean J Physiol Pharmacol.
2001 Apr;5(2):147-156.
The alteration of Ca2+-activated K+ channels in coronary arterial
smooth muscle cells isolated from isoproterenol-induced cardiac
hypertrophy in rabbit
- Affiliations
-
- 1Department of Physiology and Biophysics, College of Medicine, Inje
University, 633-165 Gaegum-dong, Busanjin-gu, Busan, South Korea.
phykimey@ijnc.inje.ac.kr
Abstract
- It has been proposed that Ca2+-activated K+ (KCa) channels play an
essential role in vascular tone. The alterations of the properties of
coronary KCa channels have not been studied as a possible mechanism for
impaired coronary reserve in cardiac hypertrophy. The present studies
were carried out to determine the properties of coronary KCa channels
in normal and hypertrophied hearts. These channels were measured from
rabbit coronary smooth muscle cells using a patch clamp technique. The
main findings of the present study are as follows: (1) the unitary
current amplitudes and the slope conductance of coronary KCa channels
were decreased without changes of the channel kinetics in
isoproterenol-induced cardiac hypertrophy; (2) the sensitivity of
coronary KCa channels to the changes of intracellular concentration of
Ca2+ was reduced in isoproterenol-induced cardiac hypertrophy. From
above results, we suggest for the first time that the alteration of KCa
channels are involved in impaired coronary reserve in
isoproterenol-induced cardiac hypertrophy.