Mineralocorticoid receptors in the ventral tegmental area regulate dopamine efflux in the basolateral amygdala during the expression of conditioned fear

Author(s)

de Oliveira, Amanda R. ^{[1, 2]} ; Reimer, Adriano E. ^{[1, 2]} ; Brandao, Marcus L. ^{[1, 2]}

Affiliation

^[1] Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Lab Psicobiol, BR-14090901 Ribeirao Preto, SP - Brazil

^[2] Inst Neurociencias & Comportamento INeC, Ribeirao Preto, SP - Brazil

• Document type: Journal article
• Source: PSYCHONEUROENDOCRINOLOGY; v. 43, p. 114-125, MAY 2014.
• Web of Science Citations: 5

Abstract

Despite the recognized involvement of corticosteroids in the modulation of emotional behavior, the specific role of mineralocorticoid receptors (MRs) and glucocorticoid receptors (GRs) in the expression of conditioned fear responses is still open to investigation. The present study sought to clarify the involvement of both types of corticosteroid receptors in two different brain regions the ventral tegmental area (VTA) and the basolateral amygdala complex (BLA) on the expression of conditioned fear. The first experiment assessed the effects of intra-VTA or intra-BLA administration of spironolactone (MR antagonist) or mifepristone (GR antagonist) on the expression of conditioned freezing to a light-CS and on motor perfo rmance in the open-field test. Intra-VTAspironolactone, but not mifepristone, attenuated the expression of the conditioned freezing response whereas intra-BLA spironolactone or mifepristone had no significant effects. These treatments did not affect motor performance in the open-field test. Since dopamine is released in the BLA from the VTA during the expression of conditioned fear, the anxiolytic-like effect of decreased corticosteroid activity in the fi rst experiment could be associated with changes in dopaminergic neurotransmission. The second experiment, using in vivo microdialysis, investigated the role of MRs in the VTA on dopamine levels in the BLA during the expression of conditioned fear. Blocking MRs loca lly in the VTAwith spironolactone reduced dopamine efflux in the BLA and decreased the expression of conditioned freezing in response to the CS. Taken together, the data indicate that corticosterone, acting locally on MRs in the VTA, stimulates dopamine efflux in the BLA, which facilitates the expression of conditioned freezing to a light-CS. (C) 2014 Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 11/00041-3 - Neurobiology of stress: the sensorimotor gating
• Grantee: Marcus Lira Brandão
• Support Opportunities: Research Projects - Thematic Grants