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.
Copyright © 2010 Elsevier B.V. All rights reserved.
Publication types
-
Comparative Study
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Action Potentials / drug effects*
-
Animals
-
Antihypertensive Agents / pharmacology*
-
Calcium Channel Blockers / pharmacology*
-
Calcium Channels, L-Type / biosynthesis
-
Calcium Channels, L-Type / genetics
-
Calcium Channels, L-Type / metabolism*
-
Cell Line
-
Cricetinae
-
Depression, Chemical
-
Dihydropyridines / pharmacology*
-
Heart Rate / drug effects
-
In Vitro Techniques
-
Isomerism
-
Kinetics
-
Male
-
Nitrophenols / pharmacology*
-
Organophosphorus Compounds / pharmacology
-
Patch-Clamp Techniques
-
Protein Isoforms / biosynthesis
-
Protein Isoforms / genetics
-
Protein Isoforms / metabolism
-
Protein Subunits / biosynthesis
-
Protein Subunits / genetics
-
Protein Subunits / metabolism
-
Rabbits
-
Recombinant Proteins
-
Sinoatrial Node / drug effects*
-
Sinoatrial Node / physiology
Substances
-
Antihypertensive Agents
-
Calcium Channel Blockers
-
Calcium Channels, L-Type
-
Dihydropyridines
-
L-type calcium channel alpha(1C)
-
Nitrophenols
-
Organophosphorus Compounds
-
Protein Isoforms
-
Protein Subunits
-
Recombinant Proteins
-
efonidipine