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Involvement of dopaminergic mechanisms in the nucleus accumbens core and shell subregions in the expression of fear conditioning.
Neurosci Lett. 2008 Dec 03; 446(2-3):112-6.NL

Abstract

The involvement of dopamine (DA) mechanisms in the nucleus accumbens (NAC) in fear conditioning has been proposed by many studies that have challenged the view that the NAC is solely involved in the modulation of appetitive processes. However, the role of the core and shell subregions of the NAC in aversive conditioning remains unclear. The present study examined DA release in these NAC subregions using microdialysis during the expression of fear memory. Guide cannulae were implanted in rats in the NAC core and shell. Five days later, the animals received 10 footshocks (0.6 mA, 1 s duration) in a distinctive cage A (same context). On the next day, dialysis probes were inserted through the guide cannulae into the NAC core and shell subregions, and the animals were behaviorally tested for fear behavior either in the same context (cage A) or in a novel context (cage B). Dialysates were collected every 5 min for 90 min and analyzed by high-performance liquid chromatography. The rats exhibited a significant fear response in cage A but not in cage B. Moreover, increased DA levels in both NAC subregions were observed 5-25 min after the beginning of the test when the animals were tested in the same context compared with accumbal DA levels from rats tested in the different context. These findings suggest that DA mechanisms in both the NAC core and shell may play an important role in the expression of contextual fear memory.

Authors+Show Affiliations

Instituto de Neurociências & Comportamento-INeC, Campus USP, 14040-901 Ribeirão Preto, SP, Brazil.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

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

Language

eng

PubMed ID

18835326

Citation

Martinez, R C R., et al. "Involvement of Dopaminergic Mechanisms in the Nucleus Accumbens Core and Shell Subregions in the Expression of Fear Conditioning." Neuroscience Letters, vol. 446, no. 2-3, 2008, pp. 112-6.
Martinez RC, Oliveira AR, Macedo CE, et al. Involvement of dopaminergic mechanisms in the nucleus accumbens core and shell subregions in the expression of fear conditioning. Neurosci Lett. 2008;446(2-3):112-6.
Martinez, R. C., Oliveira, A. R., Macedo, C. E., Molina, V. A., & Brandão, M. L. (2008). Involvement of dopaminergic mechanisms in the nucleus accumbens core and shell subregions in the expression of fear conditioning. Neuroscience Letters, 446(2-3), 112-6. https://doi.org/10.1016/j.neulet.2008.09.057
Martinez RC, et al. Involvement of Dopaminergic Mechanisms in the Nucleus Accumbens Core and Shell Subregions in the Expression of Fear Conditioning. Neurosci Lett. 2008 Dec 3;446(2-3):112-6. PubMed PMID: 18835326.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Involvement of dopaminergic mechanisms in the nucleus accumbens core and shell subregions in the expression of fear conditioning. AU - Martinez,R C R, AU - Oliveira,A R, AU - Macedo,C E, AU - Molina,V A, AU - Brandão,M L, PY - 2008/07/22/received PY - 2008/09/19/revised PY - 2008/09/22/accepted PY - 2008/10/7/pubmed PY - 2009/2/28/medline PY - 2008/10/7/entrez SP - 112 EP - 6 JF - Neuroscience letters JO - Neurosci Lett VL - 446 IS - 2-3 N2 - The involvement of dopamine (DA) mechanisms in the nucleus accumbens (NAC) in fear conditioning has been proposed by many studies that have challenged the view that the NAC is solely involved in the modulation of appetitive processes. However, the role of the core and shell subregions of the NAC in aversive conditioning remains unclear. The present study examined DA release in these NAC subregions using microdialysis during the expression of fear memory. Guide cannulae were implanted in rats in the NAC core and shell. Five days later, the animals received 10 footshocks (0.6 mA, 1 s duration) in a distinctive cage A (same context). On the next day, dialysis probes were inserted through the guide cannulae into the NAC core and shell subregions, and the animals were behaviorally tested for fear behavior either in the same context (cage A) or in a novel context (cage B). Dialysates were collected every 5 min for 90 min and analyzed by high-performance liquid chromatography. The rats exhibited a significant fear response in cage A but not in cage B. Moreover, increased DA levels in both NAC subregions were observed 5-25 min after the beginning of the test when the animals were tested in the same context compared with accumbal DA levels from rats tested in the different context. These findings suggest that DA mechanisms in both the NAC core and shell may play an important role in the expression of contextual fear memory. SN - 0304-3940 UR - https://www.unboundmedicine.com/medline/citation/18835326/Involvement_of_dopaminergic_mechanisms_in_the_nucleus_accumbens_core_and_shell_subregions_in_the_expression_of_fear_conditioning_ DB - PRIME DP - Unbound Medicine ER -