The Journal of Neuroscience, February 1, 2002, 22(3):1137-1145
Glutamate Receptor-Dependent Modulation of Dopamine Efflux in the
Nucleus Accumbens by Basolateral, But Not Central, Nucleus of the
Amygdala in Rats
John G.
Howland1,
Pornnarin
Taepavarapruk2, and
Anthony G.
Phillips1, 2
Departments of 1 Psychology and
2 Psychiatry, Brain Research Center, University of British
Columbia, Vancouver, V6T 2A1 Canada
Dopaminergic neurotransmission in the nucleus accumbens (NAc) and
neural processes in the basolateral (BLA) and central (CeN) amygdala
nuclei are implicated in associative reward learning. Given their
direct and indirect connections with the NAc and ventral tegmental area
(VTA), both the BLA and CeN may regulate the mesoaccumbens dopamine
(DA) system in rewarding situations. Electrical stimulation of the BLA
(20 Hz, 10 sec, 300 µA) induced a long-lasting 25 ± 4%
increase in DA efflux in the NAc, measured by microdialysis in freely
moving rats, whereas comparable stimulation of the CeN had no effect.
Reverse dialysis of either the NMDA receptor antagonist APV (100 µM) or the AMPA-kainate receptor antagonist DNQX (100 µM), but not the metabotropic glutamate receptor
antagonist (±)-amino-4-carboxy-methyl-phenylacetic acid (100 µM), into the NAc blocked the stimulation-evoked increase in DA efflux in the NAc. VTA infusion of lidocaine (lido; 4%) significantly reduced basal DA levels for ~30 min but failed to suppress the increase in NAc DA efflux resulting from BLA stimulation. Additionally, infusions of lido (4%) into the medial prefrontal cortex
failed to block the stimulation-evoked increase in NAc DA efflux. These
data support the hypothesis that the BLA can directly modulate DA
efflux through local mechanisms in the NAc, independent of an action on
DA cell bodies in the VTA. The finding that brief activation of the CeN
had no long-lasting effects on DA efflux in the NAc suggests an
important degree of functional independence between the CeN and BLA.
Key words:
basolateral amygdala; central amygdala; dopamine; nucleus
accumbens; glutamate; reward
Copyright © 2002 Society for Neuroscience 0270-6474/02/2231137-09$05.00/0
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