The inhibitory action of FR 34235 (a new Ca2+ entry blocker) as compared to nimodipine and nifedipine on the contractile response to norepinephrine, potassium and 5-hydroxytryptamine in rabbit basilar artery.

In isolated basilar arteries, FR 34235 (FR), a new Ca2+ entry blocker, inhibited the contractile response to potassium, norepinephrine and 5-hydroxytryptamine (5-HT) in a dose-dependent manner. The potency of the inhibitory action of FR was in the following order: potassium greater than 5-HT greater than norepinephrine. Nifedipine had a similar inhibitory action on the responses. Nimodipine had no inhibitory effect on the response to norepinephrine but suppressed the responses to potassium and 5-HT.