Laboratorio de Farmacología y Conducta, Instituto de Neurociencias, Universidad de Guadalajara, Guadalajara, Jalisco, CP 44130, Mexico.
Eur J Pharmacol. 2011 Jan 10;650(1):261-7. doi: 10.1016/j.ejphar.2010.10.029. Epub 2010 Oct 20.
The aim of the present study was to assess the effect of chronic naltrexone treatment on daily patterns of food intake in food-deprived and free-feeding rats. In experiment 1, Wistar male rats had continuous access to food and water, while in experiment 2 they were deprived of food for 12h/day. Animals in both experiments were studied as follows: a baseline period (7days), followed by a treatment period (14days) with either saline or naltrexone at 10mg/kg/day. Finally, a post-treatment period (7days) was assessed. Food and water consumption were measured every 2h after the naltrexone or saline injection for 12h and once more 12h later. Experiment 1: Food intake was higher in the naltrexone group 10h after injection. Total food intake and body weight gain were higher in the naltrexone group than in the saline group in the second week of treatment and in the post-treatment period. Experiment 2: The overeating observed in the saline group in the hours following the 12h of the food deprivation period was suppressed by naltrexone, though total daily food intake was not affected. Body weight gain was initially reduced by naltrexone, but a rebound effect was observed during the post-treatment period in the naltrexone group. Naltrexone produced a differential effect on food intake and body weight that depended on the rats' food deprivation status. These results could be explained in terms of opioid receptor up-regulation that enhances the rewarding effects of food or by naltrexone-produced changes in palatability.
本研究旨在评估慢性纳曲酮治疗对食物剥夺和自由进食大鼠日常摄食模式的影响。在实验 1 中，Wistar 雄性大鼠持续获得食物和水，而在实验 2 中，它们每天被剥夺 12 小时的食物。这两个实验中的动物如下研究：基线期（7 天），随后用生理盐水或纳曲酮（10mg/kg/天）进行治疗期（14 天）。最后，评估治疗后期（7 天）。在纳曲酮或生理盐水注射后 12 小时内，每 2 小时测量一次食物和水的摄入量，然后再过 12 小时测量一次。实验 1：注射后 10 小时，纳曲酮组的食物摄入量较高。在治疗的第二周和治疗后期间，纳曲酮组的总食物摄入量和体重增加均高于生理盐水组。实验 2：纳曲酮抑制了在 12 小时食物剥夺期后几个小时内观察到的生理盐水组的暴食行为，但总日食物摄入量不受影响。纳曲酮最初降低了体重增加，但在纳曲酮组的治疗后期间观察到了反弹效应。纳曲酮对食物摄入和体重的影响存在差异，这取决于大鼠的食物剥夺状态。这些结果可以用阿片受体上调来解释，阿片受体上调增强了食物的奖赏效应，或者可以用纳曲酮引起的适口性变化来解释。
