Amygdala β-Noradrenergic Influences on Memory Storage Involve Cholinergic Activation

doi:10.1006/nlme.1996.0006

Neurobiology of Learning and Memory

Volume 65, Issue 1, January 1996, Pages 57-64

https://doi.org/10.1006/nlme.1996.0006 Get rights and content

Abstract

These experiments examined the involvement of the amygdaloid complex as a site of interaction of adrenergic and muscarinic cholinergic influences on memory storage. Male Sprague–Dawley rats (60 days old; 250–300 g) were given a single training trial in an inhibitory avoidance task and a retention test trial 48 h later. Immediately after training buffer control or drug solutions (0.5 μl) were infused into the amygdala and, in the first experiment only, other drugs were administered intraperitoneally (ip). The first experiment examined the effects of post-training systemic injections of the muscarinic agonist oxotremorine (100.0 μg/kg) administered alone or together with intraamygdala injections of either the muscarinic antagonist atropine (1.0 μg) or the β-noradrenergic antagonist propranolol (0.3 μg). Oxotremorine enhanced retention and atropine, but not propranolol, attenuated the effects of oxotremorine. In the second experiment intraamygdala infusions of the β-noradrenergic agonist clenbuterol (10.0 ng) were administered either alone or together with atropine (1.0 μg). Clenbuterol enhanced retention and atropine blocked the effects of clenbuterol. In the third experiment intraamygdala infusions of oxotremorine (3, 10, 30, or 100 ng) were administered either alone or together with propranolol (0.3 μg). Oxotremorine (3.0 and 10.0 ng) enhanced retention and propranolol did not block the effects of oxotremorine. These findings are consistent with the view that memory storage is regulated by an interaction of β-noradrenergic and cholinergic influences and suggest that the noradrenergic influences are mediated by the release of acetylcholine and activation of muscarinic cholinergic receptors within the amygdala.

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Regular ArticleAmygdala β-Noradrenergic Influences on Memory Storage Involve Cholinergic Activation

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Amygdala β-Noradrenergic Influences on Memory Storage Involve Cholinergic Activation