Rat gambling task (rGT) is a recently developed animal model making translational research possible in psychiatric disorders related to decision-making deficits. Methiopropamine (MPA) is a structural analog to methamphetamine and a temporary controlled substance. Although increasing concerns have been raised regarding MPA's abuse, few sources of information exist regarding its psychopharmacology. Thus, we investigated whether MPA produces any changes in the choice of preference in rGT.

Rats were trained in a touch screen chamber to learn the relationships between 4 different light signals on the screen and accompanied reward outcomes and punishments set up with different schedules, for one session of 30 min each day. Once animals showed a stabilized pattern of preference, they were given a total of 5 IP injections (a single injection per day, every other day) with saline or MPA followed by 2 weeks of withdrawal. Upon MPA challenge injection, their preference of choice was re-tested in rGT chambers.

Depending upon their preference of choice, rats were separated as risk-averse or risk-seeking groups. When they were pre-exposed to and challenged with MPA, rats in the risk-averse group significantly changed their preference toward more disadvantageous choices. These effects were not shown when they were pre-exposed to saline and challenged with MPA.

These results indicate that MPA badly influences decision-making behavior as in gambling task, implying that it may aggravate pathological symptoms of bad choices, resulting in negative consequences, observed in the patients with behavioral addictions.

The authors have not supplied their declaration of competing interest.