BASIC FIBROBLAST GROWTH-FACTOR DILATES RAT PIAL ARTERIOLES

Basic fibroblast growth factor (bFGF) is a polypeptide that promotes t he survival and differentiation of brain neurons, glia, and endothelia l cells. It has been shown recently that intravenously administered bF GF lowers blood pressure by systemic vasodilation; this effect is medi ated, in part, by nitric oxide (NO)-dependent mechanisms. In the curre nt study, we directly evaluated the effect of bFGF on pial arterioles of pentobarbital-anesthetized Sprague-Dawley rats (n = 18) using the c losed cranial window technique. Basic FGF (5-200 ng/ml) produced dose- dependent vasodilation; maximal vessel diameter (similar to 120% of co ntrol) was reached at 100 ng/ml. No vasodilation was found when bFGF w as heat inactivated, or preincubated with blocking antibody. Moreover, bFGF-induced vasodilation was attenuated by coadministration of the N O synthase inhibitor N-G-nitro-L-arginine methyl ester (L-NAME), consi stent with an NO-dependent mechanism. These results suggest that bFGF may play an important role in the regulation of cerebrovascular tone a nd cerebral blood flow.