Abstract

Introduction

Materials & Methods

Results

Discussion & Conclusion

References

Discussion
Board

 MRL/lpr mice spontaneously develop a lupus-like autoimmune disease. With disease progress, MRL/lpr mice show a markedly reduced preference for sucrose (Sakic et al.,1996), suggesting decreased sensitivity to reward (anhedonia). The present study investigated the hypothesis that MRL/lpr mice exhibit anhedonia. The rewarding effects of two different doses of amphetamine (0.5mg/kg, 1.5 mg/kg) were examined using a conditioned place preference (CPP) paradigm. Each mouse was injected (i.p.) with one of the doses of amphetamine on odd numbered days and confined to its originally less preferred compartment for 30 min. On even numbered days, each mouse was injected with saline and confined to its originally more preferred compartment for 30 min. After four pairing sessions with each drug treatment, mice had unrestricted access to both compartments of the CPP apparatus and the time spent in each of the compartments was measured. Contrary to expectation, MRL/lpr mice showed a significant conditioned place preference at both doses of amphetamine, and furthermore, they did not differ from their congenic controls (MRL+/+ mice) in the extent of conditioning. These findings suggest one of two possibilities. First, MRL/lpr mice may not exhibit anhedonia after all, and the reduced intake of sucrose simply reflects an inability to taste sucrose in the same manner as controls. Or alternatively, MRL/lpr mice do exhibit anhedonia, but there is some therapeutic effect of amphetamine which makes the animals feel less sick thus accounting for the observed conditioned place preferences. Further studies are required to elucidate which of these two possibilities is most accurate.

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Poster Number PAprasad0447
Keywords: amphetamine, depression, reward, sucrose