Differentiation of response biases elicited by scopolamine and d-amphetamine: effects on habituation
The effects of scopolamine hydrobromide (2.0 mg/kg) and d-amphetamine sulfate (3.0 mg/kg) were evaluated in a water-approach task following stimulus preexposure and in the habituation of locomotor activity. Stimulus preexposure reduced the response rate of approaching a water source upon reexposure to the stimulus complex. Strain differences between DBA/2J and C57BL/6J mice were observed in the effects of the preexposure treatment, although the approach rate was directly related to the duration of preexposure in both strains. Although scopolamine and d-amphetamine differentially affected locomotor activity in the two strains, both drugs eliminated the effects of preexposure and attenuated the course of habituation of locomotor activity equally in DBA/2J and C57BL/6J mice. In addition, d-amphetamine produced carryover effects in terms of increased locomotor activity. Results were interpreted in terms of the immediate and carryover effects elicited by the drugs, i.e., response disinhibition/dishabituation in the case of scopolamine and genuine response excitation with d-amphetamine. Alternative explanations such as proactive drug effects, effects on memory consolidation, drug dissociation, or drug × deprivation interaction did not account for the observed findings.
Anisman, H, Kokkinidis, L. (Larry), Glazier, S. (Steve), & Remington, G. (Gary). (1976). Differentiation of response biases elicited by scopolamine and d-amphetamine: effects on habituation. Behavioral Biology, 18(3), 401–417. doi:10.1016/S0091-6773(76)92407-X