Evodiamine alleviates CUMS-induced depressive-like behaviours associated with modulation of uptake-2 transporters.

1. Evodiamine has been reported to exert antidepressant-like activity, but the underlying mechanisms remain incompletely understood. This study investigated the antidepressant-like effects of evodiamine and explored its regulation of monoamine neurotransmitter reuptake through modulation of uptake-2 transporters. 2. A chronic unpredictable mild stress (CUMS) mouse model was used to evaluate depressive-like behaviours. Male C57BL/6J mice were subjected to CUMS and orally administered evodiamine, while tissue levels of serotonin (5-HT), norepinephrine (NE), and dopamine (DA) in prefrontal cortex (PFC) were quantified. Monoamine uptake assays were performed in mouse brain synaptosomes and MDCK cells stably expressing human organic cation transporter 2 (hOCT2), hOCT3, or human plasma membrane monoamine transporter (hPMAT). 3. Evodiamine significantly ameliorated CUMS-induced depressive-like behaviours and restored 5-HT, NE, and DA levels in the PFC. In synaptosomes, evodiamine concentration-dependently inhibited monoamine uptake. Additional studies using selective uptake-1 inhibitors indicated that uptake-2 transporters contributed substantially to these effects. Furthermore, evodiamine potently inhibited OCT2-, OCT3-, and PMAT-mediated uptake of monoamine neurotransmitters, with the strongest inhibitory activity observed towards hOCT3-mediated transport. 4. These findings suggest that the antidepressant-like effects of evodiamine are associated with enhanced monoaminergic neurotransmission through inhibition of uptake-2 transporters, highlighting its potential as a novel therapeutic candidate for depression.