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The amygdala modulates morphine-induced state-dependent memory retrieval via muscarinic acetylcholine receptors.
Neuroscience. 2009 May 05; 160(2):255-63.N

Abstract

The current study was conducted to examine the involvement of muscarinic acetylcholine receptors of the amygdala in morphine-induced state-dependent memory retrieval. Male Wistar rats implanted bilaterally with cannulas in the amygdala were submitted to a step-through type passive avoidance task, and tested 24 h after training to measure step-through latency. Post-training s.c. administration of morphine at the doses of 5 and 7.5 mg/kg impaired the memory on the test day, which was restored when the same doses of morphine were used as a pre-test drug. This phenomenon is well known as morphine-induced state-dependent memory retrieval. Bilateral microinjection of the non-selective muscarinic acetylcholine receptor agonist, pilocarpine (0.25 and 0.5 microg/side), into the amygdala with an ineffective dose of morphine (0.5 mg/kg s.c.) significantly improved the memory retrieval and mimicked the effects of pre-test administration of a higher dose of morphine. It should be noted that in the animals that received saline after training and tested following intra-amygdala administration of pilocarpine (0.125, 0.25 and 0.5 microg/side) and those which received post-training morphine (7.5 mg/kg s.c.) and pre-test intra-amygdala microinjection of the same doses of pilocarpine, no significant change was observed in the step-through latencies. On the other hand, pre-test intra-amygdala microinjection of a selective muscarinic acetylcholine receptor antagonist scopolamine (0.125 and 0.25 microg/side) inhibited morphine-induced state-dependent memory retrieval. In addition, no significant changes were seen in memory retrieval of the animals trained before saline treatment and tested following intra-amygdala microinjection of the same doses of scopolamine (0.0625, 0.125 and 0.25 microg/side). Bilateral microinjection of scopolamine into the amygdala reversed the pilocarpine-induced potentiation of the morphine response. In view of the known actions of the drugs used, the present data point to the involvement of amygdala muscarinic acetylcholine receptors in morphine-induced state-dependent memory retrieval.

Authors+Show Affiliations

Department of Animal Biology, School of Biology, College of Science, University of Tehran, Enghelab Avenue, PO Box 4155-6455, Tehran, Iran. rezayof@khayam.ut.ac.irNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

19272427

Citation

Rezayof, A, et al. "The Amygdala Modulates Morphine-induced State-dependent Memory Retrieval Via Muscarinic Acetylcholine Receptors." Neuroscience, vol. 160, no. 2, 2009, pp. 255-63.
Rezayof A, Khajehpour L, Zarrindast MR. The amygdala modulates morphine-induced state-dependent memory retrieval via muscarinic acetylcholine receptors. Neuroscience. 2009;160(2):255-63.
Rezayof, A., Khajehpour, L., & Zarrindast, M. R. (2009). The amygdala modulates morphine-induced state-dependent memory retrieval via muscarinic acetylcholine receptors. Neuroscience, 160(2), 255-63. https://doi.org/10.1016/j.neuroscience.2009.02.069
Rezayof A, Khajehpour L, Zarrindast MR. The Amygdala Modulates Morphine-induced State-dependent Memory Retrieval Via Muscarinic Acetylcholine Receptors. Neuroscience. 2009 May 5;160(2):255-63. PubMed PMID: 19272427.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The amygdala modulates morphine-induced state-dependent memory retrieval via muscarinic acetylcholine receptors. AU - Rezayof,A, AU - Khajehpour,L, AU - Zarrindast,M R, Y1 - 2009/03/09/ PY - 2008/07/30/received PY - 2009/02/26/revised PY - 2009/02/28/accepted PY - 2009/3/11/entrez PY - 2009/3/11/pubmed PY - 2009/10/22/medline SP - 255 EP - 63 JF - Neuroscience JO - Neuroscience VL - 160 IS - 2 N2 - The current study was conducted to examine the involvement of muscarinic acetylcholine receptors of the amygdala in morphine-induced state-dependent memory retrieval. Male Wistar rats implanted bilaterally with cannulas in the amygdala were submitted to a step-through type passive avoidance task, and tested 24 h after training to measure step-through latency. Post-training s.c. administration of morphine at the doses of 5 and 7.5 mg/kg impaired the memory on the test day, which was restored when the same doses of morphine were used as a pre-test drug. This phenomenon is well known as morphine-induced state-dependent memory retrieval. Bilateral microinjection of the non-selective muscarinic acetylcholine receptor agonist, pilocarpine (0.25 and 0.5 microg/side), into the amygdala with an ineffective dose of morphine (0.5 mg/kg s.c.) significantly improved the memory retrieval and mimicked the effects of pre-test administration of a higher dose of morphine. It should be noted that in the animals that received saline after training and tested following intra-amygdala administration of pilocarpine (0.125, 0.25 and 0.5 microg/side) and those which received post-training morphine (7.5 mg/kg s.c.) and pre-test intra-amygdala microinjection of the same doses of pilocarpine, no significant change was observed in the step-through latencies. On the other hand, pre-test intra-amygdala microinjection of a selective muscarinic acetylcholine receptor antagonist scopolamine (0.125 and 0.25 microg/side) inhibited morphine-induced state-dependent memory retrieval. In addition, no significant changes were seen in memory retrieval of the animals trained before saline treatment and tested following intra-amygdala microinjection of the same doses of scopolamine (0.0625, 0.125 and 0.25 microg/side). Bilateral microinjection of scopolamine into the amygdala reversed the pilocarpine-induced potentiation of the morphine response. In view of the known actions of the drugs used, the present data point to the involvement of amygdala muscarinic acetylcholine receptors in morphine-induced state-dependent memory retrieval. SN - 1873-7544 UR - https://www.unboundmedicine.com/medline/citation/19272427/The_amygdala_modulates_morphine_induced_state_dependent_memory_retrieval_via_muscarinic_acetylcholine_receptors_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0306-4522(09)00320-0 DB - PRIME DP - Unbound Medicine ER -