Enhancement of Latent Inhibition by Chronic Mild Stress in RatsSubmitted to Emotional Response Conditioning

[摘要] This work evaluated the influence ofchronic mild stress on latent inhibition (LI) inrats, using a conditioned emotional response(CER) procedure. Rats were assigned to fourgroups: a non pre-exposed control group (NPC),a non pre-exposed stressed group (NPS), a preexposedcontrol group (PC), and a pre-exposedstressed group (PS). Stressed animals weresubmitted to a chronic mild stress (CMS)regimen for three weeks. The off-baselineconditioned emotional response procedure hadfour phases: licking response training, tone-shock conditioning, retraining, and testing.Conditioning consisted of 2 tone (30 s) andshock (0.5 s) associations. Tone-shock conditioningevidenced by NPS and NPC groupssuggests that stress did not interfere with theexpression of a conditioned emotional response.Pre-exposure was carried out using 6 tones(30 s) during 2 sessions before conditioning.Prior exposure to the tone resulted in adecrease in learning that was greater instressed animals. The results indicate anincrease in latent inhibition induced by chronicmild stress. Such LI potentiation after CMSmay be related to dopamine (DA) neurotransmissionreduction in the central nervoussystem.

[学科分类] 精神健康和精神病学