Disruption of taste trace by MK-801 administration.

Abstract

Sistemic administration of NMDA antagonists induces a disruption of Conditioned Taste Aversion when the drug is administered before stimuli presentation. However, there is scarce evidence, and such evidence is contradictory, on the role of NMDA receptors on Conditioned Taste Aversion when the drugs are injected in the interval between the Conditioned Stimulus (CS) and the Unconditioned Stimulus (US). In this paper we describe two experiments designed to analyze whether MK-801 (dizolcipine maleate) administration during the interval between the CS and the US disrupts Conditioned Taste Aversion (Experiment 1), and whether the introduction of a delay between MK-801 administration and US presentation prevents such disruption (Experiment 2). The results show the predicted Conditioned Taste Aversion disruption when the drug was injected inmediately before the US, and normal Conditioned Taste Aversion when a delay was introduced between the NMDA antagonist and the US. These results support a relevant role of NMDA receptors in encoding and consolidation of the taste memory trace.