Neurotransmitter Mechanisms in the Nucleus Accumbens Septi and Related Regions in the Rat Brain.

The present investigation compares the localization of different transmitter candidates, particularly the amino acids gamma-aminobutyrate GABA and glutamate GLU, in limbic and basal ganglia regions in the rat brain. In particular, the characteristics of nucleus accumbens septi have been studied in some detail. GABA neurons have been found in nucleus accumbens, and GABA projections from this nucleus have been identified in restricted basal forebrain and mesencephalic regions. GLU projections from the neo- or allocortex have been found to terminate in nucleus accumbens and other forebrain and hypothalamic nuclei. Neurotransmitters in local neurons have been identified in the hippocampus, nucleus accumbens, septum and caudatoputamen by means of local kainic acid injections, while neurons in the mediobasal hypothalamus have been studied after systemic treatment of newborn animals with monosodium glutamate. The results are discussed as a basis for a better understanding of limbic-basal ganglia interactions.