Amphetamine-induced conditioned place preference and modeling domains of bipolar disorder

The development of appropriate models for bipolar disorder (BPD) is a critical step in the efforts to further study the underlying pathology of the disorder and develop novel treatments. One approach to achieve better models is to develop a battery of tests for the different behavioral domains of the disease. Previous work examined ways to model reward-related behaviors in the context of BPD with some success. Because disregulation of the reward system is one of the hallmarks of BPD the present study was designed to evaluate the possibility of using amphetamine-induced conditioned place preference (CPP) as an additional method to model the reward seeking behavioral domain in BPD. To evaluate the pharmacological (predictive) validity of amphetamine-induced CPP for BPD, the study examined the effects of the prototypic mood stabilizer lithium in a biased (black/white) amphetamine-induced CPP paradigm. To delineate generalized effects of drugs, animals were also tested for locomotor activity at the end of the CPP paradigm. As expected, amphetamine pairing resulted in the development of CPP, evidenced by an increase in the time spent in the paired compartment from pre-conditioning to post-conditioning sessions. Lithium had no effects on the expression of CPP or on locomotor activity. The results suggest that amphetamine-induced CPP lacks pharmacological validity and it is therefore not a good choice as a model for the reward-seeking domain of BPD. Additional tests should be explored as suitable modes for this important component of the disorder.