INCREASED EXPRESSION OF BRAIN-DERIVED NEUROTROPHIC FACTOR BUT NOT NEUROTROPHIN-3 MESSENGER-RNA IN RAT-BRAIN AFTER CORTICAL IMPACT INJURY

Levels of brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT3) mRNA expression were measured in a rodent model of traumatic bra in injury (TBI) following unilateral injury to the cerebral cortex, To obtain reliable data on the co-expression of neurotrophin genes, adja cent coronal sections from the same rat brains were hybridized in situ with BDNF and NT3 cRNA probes, BDNF mRNA increased at 1, 3, and 5 hr after unilateral cortical injury in the cortex ipsilateral to the inju ry site and bilaterally in the dorsal hippocampus, NT3 mRNA did not ch ange significantly following injury. Our results suggest that TBI prod uces rapid increases in BDNF mRNA expression in rat brain without chan ges in NT3 mRNA expression, a finding which differs from studies of is chemia and seizures, It is possible that increased levels of BDNF mRNA rather than NT3 are important components of pathophysiological respon ses to TBI. (C) 1996 Wiley-Liss, Inc.