Abstract
We utilized Wistar rats with monocrotaline (MCT)-induced right ventricular hypertrophy (RVH) in order to evaluate the T-type Ca 2+ channel current ( I CaT) for myocardial contraction. RT-PCR provides that mRNA for T-type Ca 2+ channel α1-subunits in hypertrophied myocytes was significantly higher than those in control rats (α1G; 264 ± 36%, α1H; 191 ± 34%; P < 0.05). By whole-cell patch-clamp study, I CaT was recorded only in hypertrophied myocytes but not in control myocytes. The application of 50 nmol/L nifedipine reduced the twitch tension of the right ventricles equally in the control and RVH rats. On the other hand, 0.5 μmol/L mibefradil, a T-type Ca 2+ channel blocker, strongly inhibited the twitch tension of the RVH muscle (control 6.4 ± 0.8% vs. RVH 20.0 ± 2.3% at 5 Hz; P < 0.01). In conclusion, our results indicate the functional expression of T-type Ca 2+ channels in the hypertrophied heart and their contribution to the remodeling of excitation–contraction coupling in the cardiac myocyte.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Biochemical and Biophysical Research Communications
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
