Evaluation of samidorphan, a μ-opioid antagonist, in a drug discrimination assay in rats.

Unlabelled: Preclinical Research & Development Background: Samidorphan, a μ-opioid receptor antagonist, is in clinical development for central nervous system related diseases. The discriminative stimulus effects of samidorphan were assessed in rats trained to discriminate the effects of a known morphinan of abuse, morphine, from that of saline.

Methods: Escalating doses of samidorphan were substituted for morphine and rats were allowed to respond on two levers for food reward.

Improvements in self-administration studies based on changes in skin button type and surgical technique.

Introduction: These studies, ranging in duration from 3 to 8months, evaluated the patency and longevity of the intravenous (IV) self-administration surgical model in male Sprague Dawley rats. Surgeries were categorized and assessed based on the number of catheter and/or skin button repairs required per animal across four separate self-administration studies. Design improvements in skin button types and changes in surgical procedures were chronologically tracked and assessed.