Date of Award

5-20-2012

Document Type

Honors Thesis

Department

Neuroscience

First Advisor

Anthony Rauhut

Language

English

Abstract

Previous research has suggested the dopamine subtype-1 (D1) receptor system has a role in extinction of a conditioned response. However, the precise role of the D 1 receptor system in different memory processes (i.e., retrieval, reconsolidation) involved with extinction of conditioned responding is unknown. Thus, the present experiment determined the effect of a selective D1 receptor antagonist, SCH 23390, on extinction of methamphetamine-conditioned hyperactivity when SCH 23390 was administered immediately after the extinction sessions (i.e., targeting memory reconsolidation). Male Swiss-Webster mice received an injection (s.c.) of methamphetamine (1.0 mg/kg) associated with a locomotor activity chamber (paired) or in their home cages (unpaired) during the training phase (conditioning). Following conditioning, mice received an injection of saline prior to exposure to the locomotor activity chamber (extinction). Paired and unpaired mice received an injection (i.p.) of either SCH 23390 (0.0125, 0.025, 0.05 mg/kg) or saline immediately after the extinction sessions. Methamphetamine produced robust conditioned hyperactivity followed by extinction of conditioned hyperactivity in all paired mice. However, no dose of SCH 23390 significantly altered the rate of extinction. These results suggest that the D1 receptor may not be involved in reconsolidation of a drug-environment memory.

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