Altered sucrose self-administration following injection of melanocortin receptor agonists and antagonists into the ventral tegmental area

摘要: Alpha-melanocyte stimulating hormone (αMSH) and agouti-related protein (AgRP) are antagonistic neuropeptides that play an important role in the control of feeding body weight through their central actions on melanocortin-3 melanocortin-4 receptors. Increasing evidence indicates αMSH AgRP can interact with mesolimbic dopamine system to regulate as well other behaviors. For example, we have shown previously injection melanocortin receptor agonists antagonists into ventral tegmental area (VTA) alters both normal home-cage intake sucrose solutions, but it remains unknown whether also act VTA affect reward-related feeding. We tested agonist, MTII, or antagonist, SHU9119, directly affected operant responding maintained by pellets self-administration assays. Injection MTII decreased fixed ratio progressive schedules reinforcement, whereas SHU9119 increased under ratio, not schedules. 24-h food intake. This study demonstrates self-administration. Thus, adds critical information growing literature showing addition well-characterized controlling “need-based” feeding, behavior.