DISTRIBUTION OF N-OMEGA-NITRO-L-ARGININE FOLLOWING TOPICAL AND INTRACEREBROVENTRICULAR ADMINISTRATION IN THE RAT

The distribution of the nitric oxide synthase inhibitor, N-omega-nitro -L-arginine (L-NA), in the rat brain following either topical or intra cerebroventricular application was examined using C-14-labeled L-NA. T wo hours after topical application, the concentration of L-NA 1 mm bel ow the surface was approximately 20% of the concentration at the surfa ce, and less than 3% at 2 mm below the cortical surface. L-NA infused into the lateral cerebral ventricle distributes only in regions in clo se proximity to the ventricle even 8 h after administration. Consequen tly, intracerebroventricular administration of nitric oxide synthase i nhibitors may not be useful if global inhibition of nitric oxide synth ase is desired. (C) 1997 Elsevier Science Ireland Ltd.