We investigated the role of the alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptor antagonist 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo[f]quinoxaline (NBQX) in the expression of amphetamine-induced behavioural sensitisation and amphetamine-induced conditioned activity in mice. Repeated weekly administration of amphetamine (0.375 mg/kg) for 7 weeks led to an increased locomotor response when challenged with amphetamine 1 week later. NBQX attenuated this increased response at doses (3 and 30 mg/kg) which had no effect on the acute locomotor response to amphetamine. In a separate experiment, mice given amphetamine (1 mg/kg) in a distinctive environment, showed an increased locomotor response within this environment following a subsequent saline administration. NBQX (5-20 mg/kg) had no effect on the expression of this conditioned response. These results suggest that AMPA receptors are involved in the expression of amphetamine-induced behavioural sensitisation in mice, and that this involvement is limited to either the neurobiological effects of amphetamine or the effects of amphetamine on conditioned associations, rather than drug environment conditioned associations.