EFFECTS OF THE CALCIUM-CHANNEL BLOCKERS DOTARIZINE AND FLUNARIZINE ONCEREBROVASCULAR REACTIVITY

Dotarizine and Flunarizine are piperazine derivatives considered to be effective compounds for the treatment of various cerebrovascular diso rders. In the present study the influence of these two drugs on change s in cerebral vessel diameter and blood flow velocity were measured an d compared utilising transcranial Doppler sonography during hyperventi lation in anaesthetized cats. Drugs were administered in 15 min intrav enous infusions at a dose of 0.05 mg/kg/min. This investigation reveal ed that the 15 min intravenous administration of both compounds abolis hed the cerebral vasoconstrictor effects of hyperventilation and due t o vasodilator effects they increased blood flow velocity to initial va lues. No statistically significant differences were found between the vasodilator effects of Dotarizine and Flunarizine. Results obtained su ggest that Dotarizine, a novel piperazine derivative, has similar vaso dilator and Ca2+ channel blocking effects on cerebrovascular reactivit y compared to the widely clinically applied Flunarizine.