Autoradiographic localization of [3H]-Nisoxetine binding sites in the CNS of male and female Japanese quail

Background In the central nervous system of mammals, transporters localized on the presynaptic nerve terminals regulate the reuptake of neurotransmitters. These transporters are selective for a specific neurotransmitter such as dopamine (DA) and norepinephrine (NE). Specifically in the synapse, the dopamine transporter (DAT) reuptakes DA and the norepinephrine transporter (NET) reuptakes NE. However previous research has found that avian species do not have a gene for DAT, and therefore, birds may be using the NET to clear both NE and DA from the synapse. The current study aimed to extend this finding by localizing NET expression in male and female Japanese quail (Coturnix japonica) brains using [3H]Nisoxetine, a selective NET blocker. Results High densities of binding sites were observed in the olfactory tubercle (OTu), the medial striatum (MSt), and the lateral striatum (LSt). Lower densities of binding sites were detected in the amygdala (AMY) and hypothalamus (Hyp), and low binding was found in the medial preoptic area (mPOA) and the pallium. Conclusion The areas with the highest densities of NET are also areas that previous research has shown to have high levels of DA activity but low levels of NE innervation (e.g. striatum). The distribution of this reuptake transporter is consistent with the theory that NET acts to clear both DA and NE from the synapse.