Effects of nicardipine on vertebral vascular resistance in anesthetized dogs and spontaneous activity in mice

In 7 anesthetized dogs, vascular resistance was measured by a mercury manometer connected distally to a constant rate pump with perfusion pressure as the indication of vascular resistance. Blood taken from right carotid artery was pumped at a constant rate into left vertebral artery. Intravenous injection of nicardipine (NC) 1, 5, 10 and 20 ILg/kg produced a greater reduction of vascular resistance of vertebral artery than .that of femoral artery. While l ILg/kg exhibited a greater vasodilation in the vertebral artery than in the femoral artery, the mean arterial pressure was not markedly affected. When 175mg/kg was given po, the spontaneous activity of mice diminished (p<0.01). The acute LD60 0f NC in mice = iv 25, ig 332, and ip 123 mg/kg.