Neuropeptide Y-induced operant responding for sucrose is not mediated by dopamine |
| |
Authors: | Christina M Brown Paul J Fletcher Donald V Coscina |
| |
Institution: | ∗Section of Biopsychology, Clarke Institute of Psychiatry, University of Toronto, Toronto, Ontario, Canada;bDepartment of Psychology, Clarke Institute of Psychiatry, University of Toronto, Toronto, Ontario, Canada;cDepartment of Psychiatry, Clarke Institute of Psychiatry, University of Toronto, Toronto, Ontario, Canada;§Department of Psychology, Wayne State University, Detroit, MI, USA;¶Department of Psychiatry &; Behavioral Neurosciences, Wayne State University, Detroit, MI, USA |
| |
Abstract: | Neuropeptide Y (NPY) induces feeding in previously satiated animals after injection into the hypothalamus, especially the perifornical region (PFH). NPY also appears to have rewarding properties as evidenced by its ability to produce a conditioned place preference following injection into the nucleus accumbens (N.Acc), an effect ostensibly mediated by mesolimbic dopamine (DA). Since the progressive-ratio (PR) operant schedule has also been used to assess an organism’s motivation to respond for rewarding stimuli, we tested the possibility that NPY increases PR responding for sucrose pellets. Adult male rats were injected with NPY (0–235 pmol) bilaterally through cannulae aimed to terminate in the PFH. This produced a dose-dependent increase in the total number of responses made and the number of reinforcers earned. The DA receptor blocker, α-flupenthixol (FLU)(0–0.2 mg/kg intraperitoneally), attenuated both NPY(156 pmol)-induced and drug-free PR responding while having no effect on NPY(156 pmol)-induced free-feeding. FLU injected directly into the N.Acc (0–5 μg) also failed to reduce sucrose free-feeding. These results suggest that distinct reward mechanisms are activated during PFH NPY-induced feeding vs. PR responding, since FLU disrupted the latter but not the former. |
| |
Keywords: | Feeding Reward NPY Progressive-ratio Perifornical hypothalamus α -Flupenthixol DA |
本文献已被 ScienceDirect 等数据库收录! |
|