CALCITONIN-GENE-RELATED PEPTIDE REDUCES BRAIN INJURY IN A RAT MODEL OF FOCAL CEREBRAL-ISCHEMIA

Background and Purpose Calcitonin gene-related peptide is an endogenou s vasodilating neuropeptide with a dense concentration in the trigemin ocerebrovascular system. It is hypothesized that depletion of this pep tide contributes to delayed cerebral ischemia after subarachnoid hemor rhage and that an exogenous supply of calcitonin gene-related peptide will augment ischemic cerebral blood flow and reduce neuronal injury. Methods In this study we have investigated the effect of an intravenou s infusion of calcitonin gene-related peptide (100 ng/kg per minute), started 1 hour before and continued throughout 4 hours of focal cerebr al ischemia, on cerebral blood flow and the volume of brain injury in a rat model of middle cerebral artery occlusion. Results Calcitonin ge ne-related peptide produces a significant improvement in ischemic cere bral blood flow (32+/-2 compared with 13+/-2 mL/100 g per minute in th e controls; t=6.92 P<.0001) with a concomitant reduction in the volume of ischemic brain injury (102+/-22 compared with 234+/-19 mm(3); t=4. 47, P<.001). Conclusions These findings lend support for the potential use of this peptide in the prophylactic treatment of delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage.