POLYAMINE-ENHANCED NMDA-INDUCED BEHAVIORAL-CHANGES AND FOS-IMMUNOREACTIVITY IN RAT BRAIN

Intracerebroventricular (icy) administration of 0.5 mu mol spermidine (spd) followed by an intraperitoneal (ip) dose 50 mg/kg of N-methyl-D- aspartic acid (NMDA) resulted in long-lasting tonic-clonic seizures an d a pattern of FOS immunoreactivity (FOS-ir) which differed from that induced by a large, behaviour-modifying dose of NMDA (225 mg/kg, ip). Spd (0.5 mu mol, icy) or NMDA (50 mg/kg ip) alone did not generate FOS -ir above that produced by saline injection. Treatment with NMDA (225 mg/kg) alone and spd (0.5 mu mol, icy) combined with NMDA (50 mg/kg) r esulted in intense FOS-ir in the hippocampus. In the cerebral cortex, there was significantly less FOS-positive cells in animals treated wit h spd (0.5 mu mol, icy) and NMDA (50 mg/kg) compared to those treated with NMDA (225 mg/kg) alone. These results suggest that polyamines may play a important role in modulating the NMDA receptor signal transduc tion cascade in specific brain regions.