Desipramine induced changes in the norepinephrine transporter, α- and γ-synuclein in the hippocampus, amygdala and striatum

The high incidence of depression in Parkinson's disease (PD) has been well documented in the clinic; however, the underlying molecular mechanisms of these overlapping pathologies remain elusive. Using a rodent model of depression, the Wistar-Kyoto (WKY) rat, we previously demonstrated that in the frontal cortex the altered expression and protein interactions of α- and γ-synuclein (α-Syn, γ-Syn) were associated with dysregulated trafficking of the norepinephrine transporter (NET). Chronic treatment with desipramine (DMI), a NET-selective antidepressant, caused a disappearance of depressive-like behavior that was accompanied by a change in α-Syn and γ-Syn expression and their trafficking of NET. Using this same model, we examined the expression of NET, α-Syn and γ-Syn in the hippocampus, amygdale, brainstem, and striatum, all regions implicated in the development or maintenance of depression or PD pathology. Following chronic treatment with DMI, we observed a significant decrease in NET in the hippocampus, amygdala, and brainstem; decrease in γ-Syn in the hippocampus and amygdala; and, increase in α-Syn in the hippocampus and amygdala. Unexpectedly, we observed a significant decrease in α-Syn expression in the striatum of the WKY following chronic DMI treatment. The altered expression of NET, α-Syn and γ-Syn in different brain suggest that DMI's ability to improve depressive-like behavior in a rodent is associated with region-specific changes in the regulation of NET by α- and γ-Syn.