ACTIVATION OF NMDA RECEPTORS INCREASES BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) MESSENGER-RNA EXPRESSION IN THE HIPPOCAMPAL-FORMATION

IN the present study, it is demonstrated that activation of NMDA recep tors upregulates brain-derived neurotrophic factor (BDNF) in granule c ells of the dentate gyrus and CA3 pyramidal neurons. BDNF mRNA levels in the granule cells peaked within 4 h, were still evident at 24 h, an d returned to control levels within 48 h. In the CA3 region, BDNF mRNA levels were significantly increased at 2 h, peaked at 4 h, and return ed to control values by 8 h following NMDA treatment. Finally, the eff ects of NMDA on BDNF mRNA expression were blocked by AP5, an NMDA rece ptor antagonist. These findings provide evidence that the in vivo acti vation of NMDA receptors may regulate the expression of this neurotrop hin.