Aim To investigate the influence of intranasal delivery of calcitonin gene-related peptide(CGRP)on cerebral blood supply and expression of vascular endothelial growth factor(VEGF)following experimental subarachnoid hemorrhage(SAH).Methods Wistar rats were divided into normal control group,SAH group,intranasal normal saline(NS)+SAH group and intranasal CGRP+SAH group.SAH models were produced by double injection of autologous arterial blood into cisterna magna.CGRP and NS were given by intranasal perfusion.Dynamic observations of regional cerebral blood flow(rCBF)of cerebral cortex were made using a laser Doppler flowmeter probe.On the third day after the second cisternal injection,the expression of VEGF protein in cerebral cortex was observed by immunofluorescence method combined with laser confocal microscopic observation.Results Anatomic observation revealed that SAH models were successfully manufactured.In SAH and intranasal NS+SAH groups,a drastic and persistent drop in rCBF was noted during the observed periods.The decrease of rCBF in intranasal CGRP+SAH group was slighter as compared with that in SAH and intranasal NS+SAH groups.In SAH and intranasal NS+SAH groups,increased expression of VEGF protein in cerebral cortex was observed on the third day after second cisternal injection as compared with that in normal control group.The expression of VEGF in intranasal CGRP+SAH group was more obvious than that in intranasal NS+SAH group.Conclusion Intranasal delivery of CGRP improves cerebral blood supply and promotes angiogenesis by enhancing the expression of VEGF after SAH.