REGIONAL CHANGES IN C-FOS MESSENGER-RNA IN RAT-BRAIN AFTER IV-NMDA ORICV-NMDA NMDA INJECTIONS

THESE studies were undertaken to determine if convulsant doses of i.c. v. vs i.v. administered NMDA exhibit differential specificity for anat omical regions of the brain in stimulating c-fos. In rats i.c.v. or i. v. NMDA produced behaviorally similar clonic (popcorn) convulsions ass ociated with transient increases in c-fos mRNA in different brain area s. Transcription of c-fos mRNA peaked at 30 min post-treatment regardl ess of the route of administration. However, the route of administrati on clearly influenced the anatomical specificity of the NMDA-induced c -fos mRNA changes. For example, following i.c.v. administration maxima l stimulation in c-fos mRNA was measured in the cerebellum. In contras t, i.v. NMDA produced maximal c-fos mRNA stimulation in the cerebral c ortex. Our results demonstrate that NMDA has differential anatomical s pecificity for molecular signaling in rat brain and suggest that the r oute of NMDA administration may influence its pathophysiological respo nse.