Dual role of dopamine D2‐like receptors in the mediation of conditioned and unconditioned fear. Issue 22 (14th March 2015)

• Record Type: Journal Article
• Authors: Brandão, Marcus Lira; de Oliveira, Amanda Ribeiro; Muthuraju, Sangu; Colombo, Ana Caroline; Saito, Viviane Mitsuko; Talbot, Teddy
• Is Part Of: FEBS letters. Volume 589:Issue 22(2015)
• Page Start: 3433
• Page End: 3437
• Publication Date: 2015-03-14
• Subjects: Dopamine -- Unconditioned fear -- Conditioned fear -- Brain aversion system -- Anxiety -- Panic; Biochemistry -- Periodicals; Biophysics -- Periodicals; Molecular biology -- Periodicals; Biochimie -- Périodiques; Biochemistry; Biophysics; Molecular biology; Periodicals; 572.05
• DOI: 10.1016/j.febslet.2015.02.036
• Languages: English
• ISSNs: 0014-5793

Abstract

Abstract : A reduction of dopamine release or D2 receptor blockade in the terminal fields of the mesolimbic system, particularly the amygdala, clearly reduces conditioned fear. Similar D2 receptor antagonism in the neural substrates of fear in the midbrain tectum attenuates the processing of unconditioned aversive information. However, the implications of the interplay between opposing actions of dopamine in the rostral and caudal segments of the dopaminergic system are still unclear. Previous studies from this laboratory have reported the effects of dopaminergic drugs on behavior in rats in the elevated plus maze, auditory‐evoked potentials (AEPs) recorded from the midbrain tectum, fear‐potentiated startle, and conditioned freezing. These findings led to an interesting framework on the functional roles of dopamine in both anxiety and fear states. Dopamine D2 receptor inhibition in the terminal fields of the mesolimbic dopamine system generally causes anxiolytic‐like effects, whereas the activity of midbrain substrates of unconditioned fear are enhanced by D2 receptor antagonists, suggesting that D2 receptor‐mediated mechanisms play opposing roles in fear/anxiety processes, depending on the brain region under study. Dopamine appears to mediate conditioned fear by acting at rostral levels of the brain and regulate unconditioned fear at the midbrain level, likely by reducing the sensorimotor gating of aversive events. Abstract : Dopamine mediates unconditioned fear. Dopamine plays opposing roles in the amygdala and midbrain tectum. Dopamine D2 receptors exert modulatory actions in fear generated in the encephalic aversion system.