No evidence for a direct vasodilatory effect of celiprolol on human vasculature in vivo or in vitro.

Celiprolol is reported to be a new cardioselective beta blocker with novel ancillary properties including vasodilator effects. The purpose of this study was to investigate whether celiprolol possesses a direct vasodilatory effect on human vasculature in vivo and in vitro. We studied the in vivo effects of intra-arterial celiprolol (1-100 micrograms/min i.a.) on forearm blood flow (FBF). Forearm blood was measured by venous occlusion plethysmography. Possible vasorelaxant actions of celiprolol on human vascular smooth muscle were studied using segments of isolated human saphenous vein in vitro. The effect of celiprolol was investigated on resting tone or noradrenaline induced tone. Possible alpha 2-adrenoceptor antagonist effects of celiprolol were assessed using celiprolol as an antagonist of BHT933 induced constriction. Celiprolol was without significant effect on FBF and failed to relax isolated saphenous vein segments preconstricted with noradrenaline. The weak alpha 2-adrenoceptor antagonist action of celiprolol was demonstrable in human saphenous vein. This study does not provide evidence for a direct vasodilatory effect of celiprolol on human vasculature.