Seeley R J, Payne C J, Woods S C
Department of Psychology, University of Washington, Seattle 98195.
Am J Physiol. 1995 Feb;268(2 Pt 2):R423-7. doi: 10.1152/ajpregu.1995.268.2.R423.
Neuropeptide Y (NPY) has a potent orexigenic effect when administered either into the third ventricle or directly into hypothalamic nuclei, but the mechanism by which NPY increases intakes is poorly understood. The present study tested the ability of NPY to increase intake of the rat in the intraoral intake test, which focuses on the highly stereotyped consummatory phase of ingestion by introducing a 0.1 M sucrose solution directly into the oral cavity of rats via indwelling intraoral cannulas. Doses of 3, 9.5, and 30 micrograms of NPY, when administered into the third ventricle, all failed to change intraoral intake compared with a saline control. Food deprivation (24 h), however, nearly doubled intraoral intake. Additionally, in separate experiments, 9.5 micrograms of NPY significantly increased both 1-h food intake and 1-h bottle intake of 0.1 M sucrose. These results are consistent with two conclusions. 1) NPY does not affect the consummatory phase of ingestion. 2) NPY administration does not completely mimic the stimulus state associated with food deprivation, since food deprivation but not NPY administration increases intake in the intraoral intake test.
神经肽Y（NPY）经第三脑室给药或直接注入下丘脑核团时，具有强大的促食欲作用，但NPY增加摄入量的机制尚不清楚。本研究在经口摄入试验中测试了NPY增加大鼠摄入量的能力，该试验通过留置的口腔内插管将0.1M蔗糖溶液直接引入大鼠口腔，重点关注摄食高度刻板的完成阶段。与生理盐水对照组相比，向第三脑室注射3、9.5和30微克剂量的NPY均未能改变经口摄入量。然而，禁食（24小时）使经口摄入量几乎增加了一倍。此外，在单独的实验中，9.5微克的NPY显著增加了0.1M蔗糖的1小时食物摄入量和1小时奶瓶摄入量。这些结果与两个结论一致。1）NPY不影响摄食的完成阶段。2）给予NPY不能完全模拟与禁食相关的刺激状态，因为在经口摄入试验中，禁食而非给予NPY会增加摄入量。
