Major aim of this project is to determine the neural mechanisms involved in food intake and its conditioning effects. We microinjected the dopamine D2 receptor agonist quinpirole into the posterior ventral tegmental area (VTA), anterior VTA and substantial nigra, which temporarily inactivates dopaminergic neurons, and we examined its effects on food intake and place conditioning. We found dose-dependent effects of quinpirole. The doses of quinpirole that did not reduce food intake or induce conditioned place avoidance by itself, prevented induction of food-induced conditioned place preference (CPP). Higher doses of quinpirole induced conditioned place avoidance and reduced food intake. These results suggest that dopaminergic neurons originating from the posterior VTA play an important role in conditioned place preference induced by food reward. Qinpirole injections into the atnerior VTA or substantia nigra did not have reliable effects on CPP or food intake, suggesting that the posterior VTA plays an important role in CPP and food intake. We also found that the dose of quinpirole injected into the posterior VTA, which disrupted food CPP, prevented increase in extracellular dopmaine levels in the nucleus accumbens and that the dose of quinpirole induced conditioned place avoidance acturally decreased extracellular dopamine.
| Liu, Zhong-Hua; Shin, Rick; Ikemoto, Satoshi (2008) Dual role of medial A10 dopamine neurons in affective encoding. Neuropsychopharmacology 33:3010-20 |
