Deprivation-dependent effects of amphetamine on concurrent measures of feeding and activity

The effects of d-amphetamine (0.0, 0.5, 1.0, 2.0 mg/kg) on feeding, ambulatory activity, and rearing of male Holtzman rats were investigated in an open-field arena under 4 different conditions of food deprivation (0, 24, 48, 72 hr). Differences in the amount of food deprivation significantly influenced the drug's effect on feeding and rearing, but not on ambulatory activity. Also, differences in the amount of food deprivation appeared to more significantly and reliably influence in interrelationship (correlation) of feeding with ambulatory activity than the interrelationship of feeding with rearing or rearing with ambulatory activity. These findings suggest that the amount of food deprivation differentially influences difference concurrent measures of amphetamine effects as well as differentially affecting the interrelationship of the drug's effects. The importance of the correlation data to the potential incompatibility of amphetamine's effects as well as to an assessment of the different activity measures is briefly considered.