Alterations in dendritic morphology of hippocampal neurons in adult rats after neonatal administration of N-omega-nitro-L-arginine.

The dendritic length and dendritic-spine density of the pyramidal neurons of the prefrontal cortex and the CA1 hippocampus of rats using the nonselective nitric oxide synthase inhibitor N-omega-nitro-L-arginine (L-NNA) at different postnatal day (P) periods of the brain development (P1-P3, P4-P6, and P7-P9) were assessed using Golgi-Cox staining after puberty (P60). At P4-P6, the L-NNA treatment produced a significant decrease of the dendritic length and dendritic-spine density of the pyramidal cells of the CA1 hippocampus. In addition, the dendritic length of the pyramidal neurons of the CA1 hippocampus decreased because of the L-NNA treatment at P1-P3. These data suggest that during a specific step in the development of the brain, the nitric oxide levels may play a critical role in the morphological modifications of the pyramidal neurons of the CA1 hippocampus at postpubertal age.