Effects of Dose-Response of Topical Administration of Nimodipine on Cerebral Vasospasm After Subarachnoid Hemorrhage in Rabbits

Background: To explore the dose-response effects of topical administration of nimodipine oil cerebral vasospasm (CVS) after subarachnoid hemorrhage (SAH) in rabbits. Methods: The CVS model was established by injection of fresh autologous nonheparinized arterial blood into the subtemporal area of basilar cisterns. The 24 CVS animals were randomly divided into 4 groups, group I (n = 7): nimodipine original stock solution/normal saline = 1/19 (0.01 mg/mL); group II (n = 6): nimodipine original stock solution/normal saline = 1/9 (0.02 mg/mL); group III (n = 5): nimodipine original stock solution/normal saline = 1/4 (0.04 mg/mL); and group IV (n = 6) with no nimodipine, but 5% ethanol dissolved in normal saline as the control group. The operative area was administrated with nimodipine at different concentrations or alcohol-saline at 3 days after SAH. The blood flow velocity of middle cerebral artery was measured at 5, 15, 30, and 60 minutes after topical administration of nimodipine by transverse cerebellar diameter monitoring. Results: Blood flow velocity of middle cerebral artery in group II (0.02 mg/mL) and in group III (0.04 mg/mL) significantly decreased at 60 and 15 minutes, respectively, after topical administration of nimodipine (P < 0.05), and even more significantly at 30 and 60 minutes after topical administration of nimodipine in group III (0.04 mg/mL) (P < 0.01). Conclusion: Topical administration of nimodipine at-the concentration of 1:5 (0.04 mg/mL) and 1:10 (0.02 mg/mL) significantly alleviates CVS after SAH, which indicates that topical administration of nimodipine may be useful for CVS of patients with SAH during surgical clip of intracranial aneurysms.