The present study will investigate the interactions between histaminergic and cholinergic systems in emotional memory modulation, using two experimental models, the elevated plus-maze (EPM) and the inhibitory avoidance task (IA). Guide cannulae will be bilaterally implanted in the amygdala under stereotaxic surgery, and five days after surgical recovery, animals will receive the pharmacological treatment. In the experiment 1, mice will receive intra-amygdala infusions of saline (SAL) or scopolamine (0.02¼g/0.1¼l), muscarinic acetylcholine receptor antagonist, and ten minutes after, microinjections of SAL or Histamine (no defined), prior test. In the experiment 2, intra-amygdala infusions of SAL or chlorpheniramine (CPA) (0.16 ¼g/0.1¼l) will be administered prior test. In a second step, it will be realized microinjections of SAL or the agonist cholinergic PNU 282987 (0.3¼g/0.1¼l), five minutes after CPA infusion. According to the results of experiment 2, the interaction between the neural systems will be explored regarding the emotional memory modulation (experiment 3), in which it will be investigated if PNU 282987 microinjection actives CREB phosphorylation, using the Western Blotting technique. Mice will be submitted to the EPM (experiment 1A and 2A) and IA (experiment 1B and 2B), in two consecutive days. The decrease in open arm exploration (% entries and % time spent in the open arms) will be used as a measure of learning and memory in the EPM, and the latency time will assess the avoidance learning (IA).
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