Meguid M M, Fetissov S O, Varma M, Sato T, Zhang L, Laviano A, Rossi-Fanelli F
Neuroscience Program, Surgical Metabolism and Nutrition Laboratory, Department of Surgery, University Hospital, SUNY Upstate Medical University, Syracuse, New York 13210, USA.
Nutrition. 2000 Oct;16(10):843-57. doi: 10.1016/s0899-9007(00)00449-4.
Because daily food intake is the product of the size of a meal and the frequency of meals ingested, the characteristic of meal size to meal number during a 24-h light-dark cycle constitutes an identifiable pattern specific to normal states and obesity and that occurs during early cancer anorexia. An understanding of simultaneous changes in meal size and meal number (constituting a change in feeding patterns) as opposed to an understanding of only food intake provides a more insightful dynamic picture reflecting integrated behavior. We have correlated this to simultaneous changes in dopamine and serotonin concentrations and to their postsynaptic receptors, focusing simultaneously on two discrete hypothalamic food-intake-related nuclei, in response to the ingestion of food. The relation between concentrations of dopamine and serotonin limited to the lateral hypothalamic area (LHA) and the ventromedial nucleus (VMN) as they relate to the influence of meal size and meal number during the hyperphagia of obesity and anorexia of cancer as measured in our experiments are discussed. Based on these data, conceptual models are proposed concerning: 1) an "afferent-efferent neurotransmitter unit," with facilitatory or inhibitory neuropeptide properties to generate an appropriate neuroendocrine and neuronal response that ultimately modifies food intake; 2) initiation and termination of a meal, thereby determining the number and size of a meal under normal conditions; and 3) a schema integrating the onset mechanism of cancer anorexia. Nicotine is used as a tool to further explore the relation of meal size to meal number, with a focus on simultaneous changes in dopamine and serotonin concentrations in the LHA and VMN with the onset of acute anorexia of nicotine infusion and acute hyperphagia of nicotine cessation. Data concerning the role of sex-related hormones on dopamine and serotonin with regard to the LHA and VMN in relation to the modulation of food intake are also presented.
由于每日食物摄入量是每餐食量与用餐频率的乘积，因此在24小时明暗周期内，每餐食量与用餐次数的特征构成了一种特定于正常状态、肥胖状态以及早期癌症厌食症的可识别模式。理解每餐食量和用餐次数的同时变化（构成进食模式的改变），而不是仅仅理解食物摄入量，能提供一幅更具洞察力的动态图景，反映综合行为。我们已将此与多巴胺和血清素浓度及其突触后受体的同时变化相关联，并在摄入食物时同时关注两个离散的下丘脑食物摄入相关核团。本文讨论了在我们的实验中所测量的，肥胖症暴饮暴食和癌症厌食症期间，限于下丘脑外侧区（LHA）和腹内侧核（VMN）的多巴胺和血清素浓度与每餐食量和用餐次数影响之间的关系。基于这些数据，提出了概念模型，涉及：1）一个“传入 - 传出神经递质单元”，具有促进或抑制性神经肽特性，以产生适当的神经内分泌和神经元反应，最终改变食物摄入量；2）一餐的开始和结束，从而在正常条件下确定用餐次数和每餐食量；3）一个整合癌症厌食症发病机制的模式。尼古丁被用作一种工具，以进一步探索每餐食量与用餐次数的关系，重点关注LHA和VMN中多巴胺和血清素浓度随尼古丁输注引起的急性厌食症发作和尼古丁戒断引起的急性暴饮暴食发作的同时变化。还展示了有关性别相关激素在LHA和VMN中对多巴胺和血清素在调节食物摄入方面作用的数据。
