Dopamine D2-Like Receptors Modulate Unconditioned Fear: Role of the Inferior Colliculus |
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| Authors: | Amanda Ribeiro de Oliveira Ana Caroline Colombo Sangu Muthuraju Rafael Carvalho Almada Marcus Lira Brand?o |
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| Institution: | 1. Laboratório de Neuropsicofarmacologia, FFCLRP, Universidade de São Paulo (USP), Ribeirão Preto, São Paulo, Brazil.; 2. Instituto de Neurociências e Comportamento, INeC, Ribeirão Preto, São Paulo, Brazil.; Medical University of South Carolina, United States of America, |
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| Abstract: | BackgroundA reduction of dopamine release or D2 receptor blockade in the terminal fields of the mesolimbic system clearly reduces conditioned fear. Injections of haloperidol, a preferential D2 receptor antagonist, into the inferior colliculus (IC) enhance the processing of unconditioned aversive information. However, a clear characterization of the interplay of D2 receptors in the mediation of unconditioned and conditioned fear is still lacking.MethodsThe present study investigated the effects of intra-IC injections of the D2 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.ResultsIntra-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.ConclusionsDopamine D2-like receptors of the inferior colliculus play a role in the modulation of unconditioned aversive information but not in the fear-potentiated startle response. |
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