IFEC   20925
INSTITUTO DE FARMACOLOGIA EXPERIMENTAL DE CORDOBA
Unidad Ejecutora - UE
artículos
Título:
Involvement of dopaminergic mechanisms in the nuceleus accumbens core and shell subregions in the expression of fear conditioning
Autor/es:
MARTINEZ, R.C.; OLIVEIRA, A.R.; MACEDO, C.E.; MOLINA, V.A. AND M.L. BRANDAO
Revista:
NEUROSCIENCE LETTERS
Editorial:
Elsevier Scientific Publishers Ireland
Referencias:
Lugar: Irlanda; Año: 2008 vol. 446 p. 112 - 116
ISSN:
0304-3940
Resumen:
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 (0.6mA, 1 s duration) in a distinctive
cage A (same context). On the next day, dialysis probeswere 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 525 min
after the beginning of the test when the animalswere 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.
© 2008 Elsevier Ireland Ltd. All rights reserved.