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Muscarinic and NMDA Receptors in the Substantia Nigra Play a Role in Reward-Related Learning
BACKGROUND: Reward-related learning, where animals form associations between rewards and stimuli (i.e., conditioned stimuli [CS]) that predict or accompany those rewards, is an essential adaptive function for survival. METHODS: In this study, we investigated the mechanisms underlying the acquisition...
Autores principales: | , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Oxford University Press
2022
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9850662/ https://www.ncbi.nlm.nih.gov/pubmed/36402549 http://dx.doi.org/10.1093/ijnp/pyac076 |
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author | Galaj, Ewa Barrera, Eddy D Lynch, Olivia L Diodati, Rachel Thomas, Ashley Schneider, Piper Lenhard, Hayley Vashisht, Apoorva Ranaldi, Robert |
author_facet | Galaj, Ewa Barrera, Eddy D Lynch, Olivia L Diodati, Rachel Thomas, Ashley Schneider, Piper Lenhard, Hayley Vashisht, Apoorva Ranaldi, Robert |
author_sort | Galaj, Ewa |
collection | PubMed |
description | BACKGROUND: Reward-related learning, where animals form associations between rewards and stimuli (i.e., conditioned stimuli [CS]) that predict or accompany those rewards, is an essential adaptive function for survival. METHODS: In this study, we investigated the mechanisms underlying the acquisition and performance of conditioned approach learning with a focus on the role of muscarinic acetylcholine (mACh) and NMDA glutamate receptors in the substantia nigra (SN), a brain region implicated in reward and motor processes. RESULTS: Using RNAscope in situ hybridization assays, we found that dopamine neurons of the SN express muscarinic (mACh5), NMDA2a, NMDA2b, and NMDA2d receptor mRNA but not mACh4. NMDA, but not mACh5, receptor mRNA was also found on SN GABA neurons. In a conditioned approach paradigm, rats were exposed to 3 or 7 conditioning sessions during which light/tone (CS) presentations were paired with delivery of food pellets, followed by a test session with CS-only presentations. Intra-SN microinjections of scopolamine (a mACh receptor antagonist) or AP-5 (a NMDA receptor antagonist) were made either prior to each conditioning session (to test their effects on acquisition) or prior to the CS-only test (to test their effects on expression of the learned response). Scopolamine and AP-5 produced dose-dependent significant reductions in the acquisition, but not performance, of conditioned approach. CONCLUSIONS: These results suggest that SN mACh and NMDA receptors are key players in the acquisition, but not the expression, of reward-related learning. Importantly, these findings redefine the role of the SN, which has traditionally been known for its involvement in motor processes, and suggest that the SN possesses attributes consistent with a function as a hub of integration of primary reward and CS signals. |
format | Online Article Text |
id | pubmed-9850662 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | Oxford University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-98506622023-01-20 Muscarinic and NMDA Receptors in the Substantia Nigra Play a Role in Reward-Related Learning Galaj, Ewa Barrera, Eddy D Lynch, Olivia L Diodati, Rachel Thomas, Ashley Schneider, Piper Lenhard, Hayley Vashisht, Apoorva Ranaldi, Robert Int J Neuropsychopharmacol Regular Research Article BACKGROUND: Reward-related learning, where animals form associations between rewards and stimuli (i.e., conditioned stimuli [CS]) that predict or accompany those rewards, is an essential adaptive function for survival. METHODS: In this study, we investigated the mechanisms underlying the acquisition and performance of conditioned approach learning with a focus on the role of muscarinic acetylcholine (mACh) and NMDA glutamate receptors in the substantia nigra (SN), a brain region implicated in reward and motor processes. RESULTS: Using RNAscope in situ hybridization assays, we found that dopamine neurons of the SN express muscarinic (mACh5), NMDA2a, NMDA2b, and NMDA2d receptor mRNA but not mACh4. NMDA, but not mACh5, receptor mRNA was also found on SN GABA neurons. In a conditioned approach paradigm, rats were exposed to 3 or 7 conditioning sessions during which light/tone (CS) presentations were paired with delivery of food pellets, followed by a test session with CS-only presentations. Intra-SN microinjections of scopolamine (a mACh receptor antagonist) or AP-5 (a NMDA receptor antagonist) were made either prior to each conditioning session (to test their effects on acquisition) or prior to the CS-only test (to test their effects on expression of the learned response). Scopolamine and AP-5 produced dose-dependent significant reductions in the acquisition, but not performance, of conditioned approach. CONCLUSIONS: These results suggest that SN mACh and NMDA receptors are key players in the acquisition, but not the expression, of reward-related learning. Importantly, these findings redefine the role of the SN, which has traditionally been known for its involvement in motor processes, and suggest that the SN possesses attributes consistent with a function as a hub of integration of primary reward and CS signals. Oxford University Press 2022-11-19 /pmc/articles/PMC9850662/ /pubmed/36402549 http://dx.doi.org/10.1093/ijnp/pyac076 Text en © The Author(s) 2022. Published by Oxford University Press on behalf of CINP. https://creativecommons.org/licenses/by-nc/4.0/This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial License (https://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com |
spellingShingle | Regular Research Article Galaj, Ewa Barrera, Eddy D Lynch, Olivia L Diodati, Rachel Thomas, Ashley Schneider, Piper Lenhard, Hayley Vashisht, Apoorva Ranaldi, Robert Muscarinic and NMDA Receptors in the Substantia Nigra Play a Role in Reward-Related Learning |
title | Muscarinic and NMDA Receptors in the Substantia Nigra Play a Role in Reward-Related Learning |
title_full | Muscarinic and NMDA Receptors in the Substantia Nigra Play a Role in Reward-Related Learning |
title_fullStr | Muscarinic and NMDA Receptors in the Substantia Nigra Play a Role in Reward-Related Learning |
title_full_unstemmed | Muscarinic and NMDA Receptors in the Substantia Nigra Play a Role in Reward-Related Learning |
title_short | Muscarinic and NMDA Receptors in the Substantia Nigra Play a Role in Reward-Related Learning |
title_sort | muscarinic and nmda receptors in the substantia nigra play a role in reward-related learning |
topic | Regular Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9850662/ https://www.ncbi.nlm.nih.gov/pubmed/36402549 http://dx.doi.org/10.1093/ijnp/pyac076 |
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