Neuropharmacology
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The objective of the present work was to study the effects of an early-life stress (maternal separation, MS) in the excitatory/inhibitory ratio as a potential factor contributing to the ageing process, and the purported normalizing effects of chronic treatment with the antidepressant venlafaxine. MS induced depressive-like behaviour in the Porsolt forced swimming test that was reversed by venlafaxine, and that persisted until senescence. Aged MS rats showed a downregulation of vesicular glutamate transporter 1 and 2 (VGlut1 and VGlut2) and GABA transporter (VGAT) and increased expression of excitatory amino acid transporter 2 (EAAT2) in the hippocampus. ⋯ Chronic treatment with corticosterone recapitulated the main biochemical findings observed in MS. The different effects that chronic stress exerts in young and adult animals on expression of proteins responsible for glutamate/GABA cycling may explain the involvement of glucocorticoids in ageing-related diseases. Modulation of glutamate/GABA release may be a relevant component of the therapeutic action of antidepressants, such as venlafaxine.