Apelin-13 upregulates BDNF against chronic stress-induced depression-like phenotypes by ameliorating HPA axis and hippocampal glucocorticoid receptor dysfunctions.

•Chronic water-immersion restraint stress (CWIRS) exposure upregulated apelin and APJ levels in the rat hippocampus.•Apelin-13 ameliorated CWIRS-induced depression-like phenotypes and HPA axis hyperactivity.•Apelin-13 ameliorated CWIRS-induced hippocampal glucocorticoid receptor nucleus translocation hypoactivity.•TrkB-dependent BDNF signaling was required for apelin-13-mediated effects.