Wheel-running mitigates psychomotor sensitization initiation but not post-sensitization conditioned activity and conditioned place preference induced by cocaine in mice.

Previous literature suggests that physical exercise allowed by an unlimited access to a running wheel for several weeks can mitigate chronic neurobehavioral responsiveness to several addictive drugs in rodents. Here, the potential preventive effects of unlimited wheel-running on the initiation of psychomotor sensitization and the acquisition and extinction of conditioned place preference (CPP) induced by 10 mg/kg cocaine in C56BL/6J mice were assessed in two independent experiments. To this end, half of the mice were singly housed with a running wheel at 28 days of age for 10 weeks prior to psychopharmacological tests, during which housing conditions did not change, and the other half of mice were housed without running wheel.

Amphetamine reward in food restricted mice lacking the melanin-concentrating hormone receptor-1.

Chronic food restriction (FR) and maintenance of low body weight have long been known to increase the rewarding and motor-activating effects of addictive drugs. However, the neurobiological mechanisms through which FR potentiates drug reward remain largely unknown. Melanin-concentrating hormone (MCH) signaling could be one of these mechanisms since this peptide is involved in energy homeostasis and modulates mesolimbic dopaminergic transmission.