Title : The amygdala modulates H1-induced memory retrieval deficit via nicotinic acetylcholine receptors.
Pharmacological studies have demonstrated that histaminergic and nicotinic cholinergic receptors modulate the mechanisms involved in the amygdala-dependent memory formation. The aim of the present study was to investigate whether an agonist of the alpha 7 nicotinic cholinergic receptor (PNU-282987) into the amygdala reverses the emotional memory retrieval de?cit induced by an H1 receptor antagonist (Chlorpheniramine-CPA) in an inhibitory avoidance test. Forty adult male Swiss mice were bilaterally cannulated into the amygdala and memory retrieval was measured in an inhibitory avoidance apparatus. The animals received intra-amygdala combined microinjections of SAL or CPA (0.16 nmol), and 5 min later, microinjections of SAL or PNU (1.0 µg), prior retention test. The isolated microinjections of PNU-282987 facilitated the emotional memory, while the combined injections of PNU-282987 and CPA were able to reverse the de?cit in memory retrieval induced by CPA. These results indicated that an interaction between the histaminergic and nicotinic cholinergic systems in the amygdala modulates aversive memory retrieval in mice.