| Abstract: | To determine the source of glutamatergic input to the septum and to the nucleus accumbens septi, glutamate uptake was assessed after transections of the frontal cortex and/or fornix. Uptake in the septum and accumbens was reduced by 25 and 30% respectively, 6 days after bilateral frontal cortex transections. Both indices returned to control levels 30 days postoperatively. In contrast, while unilateral fornix transection did not affect uptake in the accumbens at either day 6 or 30, uptake in the septum was significantly reduced (25–35%) at both times. When a unilateral transection of the fornix was performed in rats with a pre-existing bilateral ablation of the frontal cortex, a further reduction in uptake was observed in the septum (50–60% at both 6 and 30 days after the fornix transection). The data implicate glutamate as a neurotransmitter in frontocortico-septal projections and suggest that the contribution of the hippocampo-septal system to total glutamate uptake in the septum is increased following ablation of the frontocortico-septal system. |
