Development of amygdaloid cholinergic mediation of passive avoidance learning in the rat

Abstract

Passive avoidance learning was studied in young rats 13-30 days of age following bilateral injections of saline or antimuscarinic and/or muscarinic agents into three amygdaloid nuclei--lateral (L), basolateral (BL), and cortical (CO). While acquisition was not influenced by saline injections into various other cerebral structures, it was significantly altered by similar injections into these amygdaloid nuclei, especially by those into the BL nucleus, suggesting that this nucleus is particularly involved in passive avoidance learning. Atropine induced significant deficits from as early as 13 days on. These deficits increased and were of similar strength after injections into any of the three studied nuclei until day 16; after that age, they diminished slightly following CO and L nuclei administration, while remaining substantial after BL nucleus injections at all ages, even at 30 days. No facilitatory effects could be elicited by arecoline injected alone, while arecoline could antagonize the disturbing effect of atropine, when given in combination, from day 13 on. These results suggest a muscarinic cholinergic mediation of passive avoidance learning through the synaptic elements located in the basal lateral part of the amygdala in the young rat.

Drug Addiction, Relapse, and the Amygdala

“…However, scopolamine just prior to expression of conditioned‐cued reinstatement fails to show an effect. These results support the role of cholinergic inputs in the formation of stimulus‐drug associations, similar to other forms of amygdalar mediated learning 49–51…”

“…Acetycholine is one of the best‐characterized neurotransmitters in mediating associative learning and memory, and the BLA is among the most densely labeled brain areas for acetylcholinesterase staining,46 with the major cholinergic projections to the BLA arising from the nucleus basalis 47,48. Whereas previous studies have examined cholinergic modulation of amygdala‐mediated forms of learning,49–51 cholinergic regulation of the BLA in a conditioned‐cue model of addiction has not been examined. Our initial experiments have shown that intra‐BLA infusion of the muscarinic receptor antagonist scopolamine produces a dose‐dependent attenuation of conditioned‐cued reinstatement, most likely by impairing the acquisition of cocaine‐paired associative learning (Fig.…”

Glucocorticoid enhancement of memory consolidation in the rat is blocked by muscarinic receptor antagonism in the basolateral amygdala

“…1996). These findings are also consistent with evidence from other laboratories indicating that muscarinic cholinergic activity in the amygdala is critical for acquisition and retention of inhibitory avoidance (Duméry & Blozovski, 1987; Decker et al . 1990; Riekkinen et al .…”

The Basomedial and Basolateral Amygdaloid Nuclei Contribute to the Induction of Long‐term Potentiation in the Dentate Gyrus In Vivo

“…l), which functionally interact with each other (Krettek and Price, 1978;Ottersen, 1982;Aggleton, 1985;Smith and Pare, 1994) and play different roles in learning and memory (Dumery and Blozovski, 1987;Hatfield et al, 1992;Ohno et al, 1992;Tomaz et al, 1992). In our previous study (Ikegaya et al, 1994).…”