Interaction of arena size with different measures of amphetamine effects.

The effects of d-amphetamine (0.0, 0.5, 1.0. 2.0 mg/kg) on feeding and activity of male Holtzman rats were investigated in 3 different size test arenas. Differences in the size of arenas significantly altered the drug's effect on ambulatory activity, but not on feeding or rearing. Also, differences in the size of arenas significantly altered the interrelationship (correlation) of amphetamine's effects on feeding and ambulatory activity, but not the interrelationship of the drug's effects on feeding and rearing. These findings suggest that test arena size differentially influences different general measures of amphetamine effects as well as differentially affecting the interrelationship of amphetamine effects. The importance of the interrelationship (correlation) data to the potential incompatability of the drug's effects is briefly considered.