(R)-(+)-Bay K 8644 is a L-type calcium channel protein blocker with negative inotropic effects. (R)-(+)-Bay K 8644 is an enantiomer showing opposite effects to the racemate (±)-Bay K 8644 and and (S)-(−)-Bay K8644. Intracerebroventricular administration of this enantiomer has no effect on motor function in mice, whereas (−)-BAY-K-8644 impairs rotarod and motor activity, an effect that is blocked by (+)-BAY-K-8644.