Antidepressant augmentation upon intranasal Galanin and Neuropeptide Y agonists enhanced ventral hippocampal proliferative and neurotrophic actions

Abstract

Background and Purpose: Dysregulation of adult hippocampal neurogenesis is linked to major depressive disorder (MDD), with more than 300 million people diagnosed and worsened by the COVID-19 pandemic. Accumulating evidence for Neuropeptide Y (NPY) and galanin (GAL) interaction was shown in various limbic system regions at molecular-,cellular- and behavioral-specific levels. The purpose of the current work was to evaluate the proliferating role of GALR2 and Y1R agonists interaction upon intranasal infusion in the ventral hippocampus. Experimental approach: We studied their hippocampal proliferating actions using the proliferating cell nuclear antigen (PCNA) and the expression of of the brain-derived neurothrophic factor (BDNF). Moreover, we studied the formation of Y1R-GALR2 heteroreceptor complexes and analyzed morphological changes on hippocampal neuronal cells. Finally, the functional outcome of the NPY and GAL interaction on the ventral hippocampus was evaluated in the forced swimming test. Key Results: We demonstrated that the intranasal infusion of GALR2 and the Y1R agonists promotes cell proliferation in the DG of the ventral hippocampus and the induction of the neurotrophic factor BDNF. These effects were mediated by the increased formation of Y1R-GALR2 heteroreceptor complexes, which may mediate the neurites outgrowth observed on neuronal hippocampal cells. Importantly, BDNF action was found necessary for the antidepressant-like effects after GALR2 and the Y1R agonists intranasal administration. Conclusions & Implications: Our data may suggest the translational development of new heterobivalent agonist pharmacophores acting on Y1R–GALR2 heterocomplexes in the ventral hippocampus for the novel therapy of mayor depression disorder or depressive-affecting diseases.