纳络酮、地卓西平(MK-801)对大鼠食物渴求的影响

实验以条件性位置偏爱（CPP）的表达为渴求模型观察纳络酮及MK-801对大鼠食物CPP表达，探讨摄食行为调控的心理机制。48只SD大鼠分成食物组（24）与对照组（24），3轮食物匹配训练后，在CPP表达前分别注射生理盐水、纳络酮（1.0 mg˙kg -1）及MK-801(0.1 mg˙kg -1)，观察各组动物在食物匹配训练侧停留时间的变化。结果发现，MK-801促进食物CPP的表达，但纳络酮对食物CPP的表达没有显著影响。以上结果表明MK-801（0.1mg˙kg -1）增强动物的食物渴求至少是其增加摄食量的原因之一，而1.0 mg˙kg -1的纳络酮降低动物的摄食量并不是由于食物渴求的下降导致的。MK-801与纳络酮调节动物摄食行为的心理机制可能不一致。

EFFECT OF NALOXONE AND DIZOCILPINE ON FOOD CRAVING IN RATS

Ingestive behavior was evolutionarily important for survival in animals. A serial of studies demonstrated that dizocilpine (MK-801) increased but naloxone decreased the food intake in rats. However, it was elusive how they mediated ingestive behavior in rats. Food craving was one of the most important factors to impact food intake. In the present experiment, the effects of naloxone and dizocilpine on food craving of the rats were investigated with conditioned place preference (CPP) paradigm. After received 3 conditioning sessions with food, the rats were injected with saline, naloxone (1.0 mg˙kg -1) and MK-801 (0.1 mg˙kg -1) during the expression of CPP test, and the time spent in the food-associated compartment were observed. The results showed the rats developed significant preference for food-paired side, and MK-801 potentiated the expression of food-induced CPP, but naloxone had no effect on the expression of food CPP. The present data suggested that the enhancement of food craving was one of the possibilities of MK-801-induced increase of food intake, but it might not be the reduction of food craving that led to the naloxone-induced decrease of food intake. The psychological mechanism of ingestive behavior meditated by naloxone and MK-801 may be disassociated.