Selective vasodilatory effect of dipfluzine on vertebral artery in anesthetized dogs

Dipfluzine (Dip) is a novel calcium antagonist first developed by Department of Chemistry, Beijing University. The effects of Dip on hemodynamics and vascular resistance in vertebral (VVR), coronary (CVR), and femoral (FVR) arteries were compared with those of cinnarizine (Cin) in anesthetized dogs. Dip iv decreased dose-dependently VVR at 0.1, 0.3, 1, and 3 mg.kg-1, CVR at 3 mg.kg-1, and FVR at 1 and 3 mg.kg-1. The fall of VVR by Dip iv was more remarkable than that by Cin at the matching doses. The systolic, diastolic, and mean blood pressure and total peripheral resistance were temporarily reduced equally by both of them at 1 mg.kg-1 iv, while Dip and Cin produced no obvious changes in heart rate, cardiac index, stroke index, LVP, and dP/dtmax at all doses. These results suggested that Dip possessed a high selectivity at different sites of the vasculature and was a more potent selective cerebral vasodilator than Cin.