IngentaConnect Role of basolateral amygdala dopamine in modulating prepulse inhi...

Abstract:

The dopamine (DA) projection to the basolateral amygdala (BLA) modulates nucleus accumbens (NAc) and medial prefrontal cortex (mPFC) DA transmission. Given the involvement of the BLA, and of NAc and mPFC DA, in select forms of information processing, we sought to determine the role of BLA DA in modulating prepulse inhibition (PPI) and latent inhibition (LI).

The effects of BLA D₁ (SCH 23390) and D₂/D₃ (raclopride) receptor blockade on PPI and LI were examined.

Separate groups of male Long–Evans rats received bilateral intra-BLA infusions of SCH 23390 (3.2 or 6.4 μg/0.5 μl per side), raclopride (2.5 or 5.0 μg/0.5 μl per side) or saline prior to testing. In two experiments, the effects of BLA DA receptor antagonism on PPI of the acoustic startle response (ASR) and LI of conditioned taste aversion were determined. A control group received bilateral intra-striatal infusions of SCH 23390 or raclopride prior to PPI testing.

Intra-BLA SCH 23390 or raclopride had no effect on the ASR. Intra-BLA SCH 23390 enhanced and raclopride disrupted PPI, both in a dose-related manner. Intra-striatal SCH 23390 or raclopride had no effect on PPI or ASR magnitude. Finally, BLA DA receptor blockade had no effect on LI.

These results indicate that PPI is modulated by BLA DA and suggest that this modulation occurs independently of changes in NAc and/or mPFC DA transmission. They also suggest that BLA DA is not involved in modulating LI and add to evidence indicating that PPI and LI are mediated by different neural substrates.

Keywords: Acoustic startle response; Conditioned taste aversion; D1 receptor; D2/D3 receptor; Raclopride; SCH 23390; Sensorimotor gating

Document Type: Research article

DOI: 10.1007/s00213-004-1879-6

Affiliations: 1: Douglas Hospital Research Centre, McGill University, 6875 Boulevard LaSalle, Montreal (Verdun), QC, Canada, H4H 1R3, 2: Douglas Hospital Research Centre, McGill University, 6875 Boulevard LaSalle, Montreal (Verdun), QC, Canada, H4H 1R3, Email: gratal@douglas.mcgill.ca

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Role of basolateral amygdala dopamine in modulating prepulse inhibition and latent inhibition in the rat