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Distribution of norepinephrine transporters in the non-human primate brain

Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA.
Neuroscience (Impact Factor: 3.33). 02/2006; 138(2):703-14. DOI: 10.1016/j.neuroscience.2005.11.033
Source: PubMed

ABSTRACT Noradrenergic terminals in the central nervous system are widespread; as such this system plays a role in varying functions such as stress responses, sympathetic regulation, attention, and memory processing, and its dysregulation has been linked to several pathologies. In particular, the norepinephrine transporter is a target in the brain of many therapeutic and abused drugs. We used the selective ligand [(3)H]nisoxetine, therefore, to describe autoradiographically the normal regional distribution of the norepinephrine transporter in the non-human primate central nervous system, thereby providing a baseline to which alterations due to pathological conditions can be compared. The norepinephrine transporter in the monkey brain was distributed heterogeneously, with highest levels occurring in the locus coeruleus complex and raphe nuclei, and moderate binding density in the hypothalamus, midline thalamic nuclei, bed nucleus of the stria terminalis, central nucleus of the amygdala, and brainstem nuclei such as the dorsal motor nucleus of the vagus and nucleus of the solitary tract. Low levels of binding to the norepinephrine transporter were measured in basolateral amygdala and cortical, hippocampal, and striatal regions. The distribution of the norepinephrine transporter in the non-human primate brain was comparable overall to that described in other species, however disparities exist between the rodent and the monkey in brain regions that play a role in such critical processes as memory and learning. The differences in such areas point to the possibility of important functional differences in noradrenergic information processing across species, and suggest the use of caution in applying findings made in the rodent to the human condition.

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    • "Judging from the distribution of NE-positive fibers, there is a light innervation by DBH immunoreactive fibers in the region associated with the PL, with a slightly heavier distribution occurring medially (Sadikot and Parent, 1990). The distribution of NE in the Macaque has only been described using [ 3 H]nisoxetine, a selective ligand for the NE transporter; levels in the PL appear low to moderate, although specific reference to the PL was not included (Smith et al., 2006). With regards to NE receptors in the PL, an autoradiographic study in the tree shrew reveals that the PL contains a high number of binding sites for α 1 and α 2 receptors and a low number of β binding sites (Flugge et al., 1994). "
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