Determining the Physiological Effects of Opioid Addiction through the Application of Spared Nerve Injury Model of Neuropathic Pain on the Morphine Self-Administration Rodent Model
The aim of this project is to determine whether morphine reinforcement and seeking behavior in enhanced in SNI mice trained to self-administer morphine. Testing was completed by examining behavioral approaches of both SNI and sham lesioned mice, with a focus in MSA. Mice were tested 2 months after catheter implantation, with active doses of 0.1/mg/kg/infusion. An FR1, 13 days training procedure was used, with each level press triggering illumination of the cue light for 6 seconds and the in-house light for 20 seconds to indicate a timeout period. To determine the reinforcing capacity of the morphine, a progressive ratio schedule was used to quantify seeking behavior extinction and reinstatement through drug-primed and pain-induced reinstatement, which showed a clear distinction between SNI and Sham addiction patterns. These results can be used to guide chemogenetic manipulation of key nodes in the VTA-NAc circuitry in an attempt to reverse SNI-induced changes in drug seeking behavior; particularly regarding the VTA DA neurons that intersection the shell and core as well as investigating if the MSA alters the SNI induced adaptations
