Effect of Calcium Antagonist(Nicardipine) on CBF, CMRO2, and CMRG in Experimental Cerebral Vasopasm

ABSTRACT

The author investigated the cerebral circulatory and metabolic effects of systemic and intracisternal administration of nicardipine in a canine model of chronic cerebral vasospasm. Twenty-one dogs were assigned to one of three groups; control, intravenous nicardipine, and intracisternal nicardipine. All animals received a total of 12 ml of fresh unheparinized autologous blood via three cisternal injections. Sequential measurements of cerebral blood flow(CBF), cerebral metabolic rate of oxygen(CMRO2), and cerebral metabolic rate of glucose(CMRG) were chacked four times in nine days. Animals were sacrificed at Day 9 and amount of clot remained in brainstem and basal cistern was graded accordingly. Significant improvement of cerebral blood flow was noted in Day 6, Day 9 of intracisternal group and in Day 3, Day 6 of intravenous group(each, p<0.05) with slight better results seen in intracisthernal group. Results of sequential changes of CMRO2 and CMRG indicated possible role of nicardipine in protective effects on deleterious neuronal damage following ischemic changes after vasospasm, but definitive statements on this subject matter should be reserved until further study, espedially on morphologic examinations is carried on, Significantly less amount of clot remained in intracisthernal group may be due to effects of nicardipine in its inhibitory action on platelet aggregation, and/or stimulatory effect on prostacyclin production. These factors along with other possible factors should be speculated.