Activation of post-synaptic 5-HT1A receptors in the dorsal hippocampus prevents learned helplessness development

摘要: Abstract Activation of post-synaptic 5-HT1A receptors in the dorsal hippocampus is proposed to mediate stress adaptation. Chronic social and high corticosteroid levels would impair this coping mechanism, predisposing animals learned helplessness. To test hypothesis that increasing serotonin attenuate development helplessness, rats received inescapable foot-shock (pre-test session) were tested a shuttle box 24-h later. Pre-stressed showed impairment escape responses. This effect was prevented by chronic (21 days) treatment with imipramine (15 mg/kg). Similar results obtained when bilateral intra-hippocampal injections, immediately after pre-test, zimelidine (100 nmol/0.5 μl), reuptake blocker, or 8-OH-DPAT (10 nmol), receptor agonist. The pre-treatment WAY-100635 (30 antagonist. These data suggest facilitation serotonergic neurotransmission mediates adaptation severe stress, probably through activation receptors.