PubMed 17662243

Referenced in Channelpedia wiki pages of: none

Automatically associated channels: Cav1.2

Title: Oestrogen directly inhibits the cardiovascular L-type Ca2+ channel Cav1.2.

Authors: Nina D Ullrich, Alexandra Koschak, Kenneth T MacLeod

Journal, date & volume: Biochem. Biophys. Res. Commun., 2007 Sep 21 , 361, 522-7

PubMed link:

Oestrogen can modify the contractile function of vascular smooth muscle and cardiomyocytes. The negative inotropic actions of oestrogen on the heart and coronary vasculature appear to be mediated by L-type Ca(2+) channel (Ca(v)1.2) inhibition, but the underlying mechanisms remain elusive. We tested the hypothesis that oestrogen directly inhibits the cardiovascular L-type Ca(2+) current, I(CaL). The effect of oestrogen on I(CaL) was measured in Ca(v)1.2-transfected HEK-293 cells using the whole-cell patch-clamp technique. The current revealed typical activation and inactivation profiles of nifedipine- and cadmium-sensitive I(CaL). Oestrogen (50 microM) rapidly reduced I(CaL) by 50% and shifted voltage-dependent activation and availability to more negative potentials. Furthermore, oestrogen blocked the Ca(2+) channel in a rate-dependent way, exhibiting higher efficiency of block at higher stimulation frequencies. Our data suggest that oestrogen inhibits I(CaL) through direct interaction of the steroid with the channel protein.