Dopamine D-2-Like Receptors Modulate Unconditioned Fear: Role of the Inferior Colliculus

Author(s)

de Oliveira, Amanda Ribeiro ^{[1, 2]} ; Colombo, Ana Caroline ^{[1, 2]} ; Muthuraju, Sangu ^{[1, 2]} ; Almada, Rafael Carvalho ^{[1, 2]} ; Brandao, Marcus Lira ^{[1, 2]}

Affiliation

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

^[2] INeC, Ribeirao Preto, SP - Brazil

• Document type: Journal article
• Source: PLoS One; v. 9, n. 8 AUG 18 2014.
• Web of Science Citations: 9

Abstract

Background: A reduction of dopamine release or D-2 receptor blockade in the terminal fields of the mesolimbic system clearly reduces conditioned fear. Injections of haloperidol, a preferential D-2 receptor antagonist, into the inferior colliculus (IC) enhance the processing of unconditioned aversive information. However, a clear characterization of the interplay of D-2 receptors in the mediation of unconditioned and conditioned fear is still lacking. Methods: The present study investigated the effects of intra-IC injections of the D-2 receptor-selective antagonist sulpiride on behavior in the elevated plus maze (EPM), auditory-evoked potentials (AEPs) to loud sounds recorded from the IC, fear-potentiated startle (FPS), and conditioned freezing. Results: Intra-IC injections of sulpiride caused clear proaversive effects in the EPM and enhanced AEPs induced by loud auditory stimuli. Intra-IC sulpiride administration did not affect FPS or conditioned freezing. Conclusions: Dopamine D-2-like receptors of the inferior colliculus play a role in the modulation of unconditioned aversive information but not in the fear-potentiated startle response. (AU)

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