Idaho State University, Department of Psychology, Mail Stop 8112, Pocatello, ID 83209-8112, USA.
Physiol Behav. 2012 Feb 1;105(3):734-41. doi: 10.1016/j.physbeh.2011.10.009. Epub 2011 Oct 12.
Research on free-food intake suggests that cannabinoids are implicated in the regulation of feeding. Few studies, however, have characterized how environmental factors that affect food procurement interact with cannabinoid drugs that reduce food intake. Demand analysis provides a framework to understand how cannabinoid blockers, such as rimonabant, interact with effort in reducing demand for food. The present study examined the effects rimonabant had on demand for sucrose in obese Zucker rats when effort to obtain food varied and characterized the data using the exponential ("essential value") model of demand. Twenty-nine male (15 lean, 14 obese) Zucker rats lever-pressed under eight fixed ratio (FR) schedules of sucrose reinforcement, in which the number of lever-presses to gain access to a single sucrose pellet varied between 1 and 300. After behavior stabilized under each FR schedule, acute doses of rimonabant (1-10mg/kg) were administered prior to some sessions. The number of food reinforcers and responses in each condition was averaged and the exponential and linear demand equations were fit to the data. These demand equations quantify the value of a reinforcer by its sensitivity to price (FR) increases. Under vehicle conditions, obese Zucker rats consumed more sucrose pellets than leans at smaller fixed ratios; however, they were equally sensitive to price increases with both models of demand. Rimonabant dose-dependently reduced reinforcers and responses for lean and obese rats across all FR schedules. Data from the exponential analysis suggest that rimonabant dose-dependently increased elasticity, i.e., reduced the essential value of sucrose, a finding that is consistent with graphical depictions of normalized demand curves.
关于自由进食的研究表明，大麻素参与了摄食的调节。然而，很少有研究描述影响食物获取的环境因素与减少食物摄入的大麻素药物如何相互作用。需求分析提供了一个理解大麻素阻滞剂（如利莫那班）如何与减少食物需求的努力相互作用的框架。本研究考察了利莫那班对肥胖 Zucker 大鼠蔗糖需求的影响，当获取食物的努力程度不同时，并使用需求的指数（“基本价值”）模型对数据进行了特征描述。29 只雄性（15 只瘦，14 只胖） Zucker 大鼠在 8 种固定比率（FR）的蔗糖强化方案下按压杠杆，其中获得单个蔗糖丸的按压次数从 1 到 300 不等。在每个 FR 方案下行为稳定后，在一些会议前给予利莫那班（1-10mg/kg）的急性剂量。在每种条件下，食物强化物的数量和反应被平均，指数和线性需求方程被拟合到数据中。这些需求方程通过其对价格（FR）增加的敏感性来量化强化物的价值。在载体条件下，肥胖 Zucker 大鼠在较小的固定比率下比瘦大鼠消耗更多的蔗糖丸；然而，它们对两种需求模型的价格上涨都同样敏感。利莫那班在所有 FR 方案中均剂量依赖性地减少了瘦大鼠和肥胖大鼠的强化物和反应。指数分析的数据表明，利莫那班剂量依赖性地增加了弹性，即降低了蔗糖的基本价值，这一发现与归一化需求曲线的图形描述一致。
