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Differential corticosteroid receptor regulation of mesoaccumbens dopamine efflux during the peak and nadir of the circadian rhythm : a molecular equilibrium in the midbrain?

Tye, Susannah J., Miller, Anthony D. and Blaha, Charles D. 2009, Differential corticosteroid receptor regulation of mesoaccumbens dopamine efflux during the peak and nadir of the circadian rhythm : a molecular equilibrium in the midbrain?, Synapse, vol. 63, no. 11, pp. 982-990, doi: 10.1002/syn.20682.

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Title Differential corticosteroid receptor regulation of mesoaccumbens dopamine efflux during the peak and nadir of the circadian rhythm : a molecular equilibrium in the midbrain?
Author(s) Tye, Susannah J.
Miller, Anthony D.
Blaha, Charles D.
Journal name Synapse
Volume number 63
Issue number 11
Start page 982
End page 990
Total pages 9
Publisher John Wiley & Sons
Place of publication Hoboken, N. J.
Publication date 2009-11
ISSN 0887-4476
1098-2396
Keyword(s) corticosterone
mineralocorticoid
glucocorticoid
chronoamperometry
ventral tegmentum
Summary Corticosteroid receptor modulation of mesoaccumbens dopamine neurotransmission is believed to be a key neurobiological mechanism mediating the effects of stress in addiction. Importantly, nucleus accumbens (NAc) subregions (core and shell) are reported to respond differentially to fluctuating basal levels of glucocorticoids, with dopaminergic responses in the core of the NAc being somewhat impervious to fluctuating levels of glucocorticoids relative to the shell. To investigate the corticosteroid receptor mechanisms mediating basal dopamine efflux in the core of the NAc, we have used chronoamperometry in combination with stearate-modified graphite paste electrodes in urethane anesthetized male Long–Evans rats during the peak and nadir of the circadian cycle. Blockade of ventral tegmental area low-affinity glucocorticoid (GR) or high-affinity mineralocorticoid (MR) receptors with mifepristone (1 μg/μl) or spironolactone (0.2 μg/μl), respectively, indicated that endogenous phase-dependent corticosteroid receptor activation (GRs during peak; MRs during nadir) facilitated extracellular NAc dopamine efflux. Conversely, the alternate receptor's actions appeared inhibitory at these time points (MRs during peak; GRs during nadir). Pharmacological activation of either the GR or MR with corticosterone (2 μg/μl) or aldosterone (0.2 μg/μl), respectively, potentiated NAc dopamine efflux, irrespective of circadian phase. Together, these data suggest that dominant corticosteroid receptor activation stimulates tonic mesoaccumbens dopamine transmission, enabling MRs and GRs to differentially maintain basal NAc dopamine release over the course of the circadian cycle. This points to an important molecular mechanism through which relatively stable NAc core dopamine extracellular levels could be maintained in the face of fluctuating corticosterone circadian rhythms.
Language eng
DOI 10.1002/syn.20682
Field of Research 170101 Biological Psychology (Neuropsychology, Psychopharmacology, Physiological Psychology)
Socio Economic Objective 920111 Nervous System and Disorders
HERDC Research category C1.1 Refereed article in a scholarly journal
Copyright notice ©2009, Wiley-Liss, Inc.
Persistent URL http://hdl.handle.net/10536/DRO/DU:30047696

Document type: Journal Article
Collection: School of Psychology
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