抄録
Experimental delayed vasospasm was produced by topical application of a 3-day-old incubated blood-CSF mixture on the feline basilar artery which was exposed transclivally on the third day after the injection of blood into the cisterna magna. The effect of calcium antagonists on both rCBF in the brain stem and arterial blood pressure was studied. rCBF was measured by heat clearance method.
Intravenous administration of nifedipine, nicardipine, verapamil, cinnarizine and diltiazem produced mild to moderate hypotension in a dose of greater than 0.003, 0.01, 0.2, 0.65, 0.07mg/kg respectively.
A prolonged increase of rCBF was observed in 43% of the cats with mild hypotension induced by nifedipine. Nicardipine and verapamil also demonstrated the prolonged increase of rCBF in 18% and 6% of the cases respectively. When moderate hypotension was produced by each of calcium antagonists, a prolonged increase of rCBF was noted in 25% of the cases treated with nifedipine, 18% with nicardipine, and 43% with verapamil. Cinnarizine and diltiazem showed only a transient increase of rCBF which lasted no more than 10 minutes.
These results indicate that calcium antagonists used in this study may act mainly on the extracranial rather than intracranial vessels. Further study is required to apply these chemicals for patients with cerebral vasospasm.
