Activation of GABA-B receptors induced by systemic amphetamine abolishes dopamine release in the rat lateral septum

The lateral septum is a brain nucleus involved in various mental disorders such as anxiety and drug addiction. In the present study, we investigated whether systemic amphetamine, known to release dopamine (DA) in nucleus accumbens, will also release DA in lateral septum. Our results show that systemic amphetamine administration (2 mg/kg i.p.) induced a significant increase in DA extracellular levels in nucleus accumbens but not in lateral septum. Interestingly, intralateral septum perfusion of amphetamine through the microdialysis probe induced a significant increase in DA extracellular levels. To test if GABAergic neurotransmission in lateral septum was responsible for inhibiting the release of DA when amphetamine was administered systemically, we perfused a GABA-B selective antagonist (CGP-52432) intra lateral septum. Systemic amphetamine administration induced a significant increase in lateral septum DA release when CGP-52432 was concomitantly superfused. Our results indicate that the systemic administration of amphetamine induces an increase in lateral septum GABA release and the consequent activation of GABA-B receptors counteracting the direct effect of amphetamine on lateral septum DA release.