LAUSR

The psychostimulant methamphetamine (Met), similarly to other drugs of abuse, is known to pro-duce an increased behavioural response after its repeated application (behavioural sensitisation). It has also been described that an increased response to a drug may be elicited by previous repeated administration of another drug (cross-sensitisation). We have previously shown that the CB1, CB2 and TRPV (vanilloid) cannabinoid receptor agonist methanandamide, cross-sensitised to Met stimulatory effects in mice. The present study was focused on ability of the more selective and potent CB1 receptor activator arachidonylcyclopropylamide (ACPA) to elicit cross-sensitisation to the stimulatory effects of Met on mouse locomotor behaviour in the Open field test. Male mice were randomly divided into three groups and on seven occasions (from the 7th to 13th day of the experiment) were administered drugs as follows:(a) n1: vehicle at the dose of 10 ml/kg/day; (b) n2: Met at the dose of 2.5 mg/kg/day; (c) n 3: ACPA at the dose of 1.0 mg/kg/day. Locomotor behaviour in the Open field test was measured (a) after administration of vehicle on the 1st experimental day, (b) after the 1st dose of drugs given on the 7th day, and (c) on the 14th day after drugs as follows:(a) n1: vehicle at the dose of 10 ml/kg/day; (b) n2: Met at the dose of 2.5 mg/kg/day; (c) n 3: ACPA at the dose of 1.0 mg/kg/day.