Referenced in: none

Automatically associated channels: Cav3.1 , Slo1

Title: Effects of S(+)-efonidipine on the rabbit sinus node action potential and calcium channel subunits Ca(V)1.2, Ca(V)1.3 and Ca(V)3.1.

Authors: Hikaru Tanaka, Iyuki Namekata, Toru Ogawa, Yayoi Tsuneoka, Chisa Komikado, Akira Takahara, Naoko Iida-Tanaka, Hiroko Izumi-Nakaseko, Hiromichi Tsuru, Satomi Adachi-Akahane

Journal, date & volume: Eur. J. Pharmacol., 2010 Dec 15 , 649, 263-7

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/20858482

Abstract
The effect of S(+)-efonidipine on sinus node action potential and calcium channel α-subunits was examined. The slope of the phase 4 depolarization of isolated rabbit sinus node tissue was significantly reduced by S(+)-efonidipine (1 μM), slightly reduced by nifedipine (1 μM), but was not affected by R(-)-efonidipine. S(+)-efonidipine (1 μM), inhibited the expressed Ca(V)1.2, Ca(V)1.3 and Ca(V)3.1 channel currents by 75.7%, 75.3% and 94.0%, nifedipine 84.0%, 43.2% and 14.9%, and R(-)-efonidipine 30.0%, 19.6% and 92.8%, respectively. Thus, the prolongation of the phase 4 depolarization of the rabbit sinus node by S(+)-efonidipine may be explained by blockade of the Ca(V)1.3 channel current.