Opposite effects of MK-801 on the expression of food and morphine-induced conditioned place preference in rats.
Behavioural studies have provided strong evidence for common substrates in the rewards of natural and addictive substances, but it is still unclear whether there is a common glutamatergic NMDA receptor mechanism involved in the processing of reward for both. The present study was designed to investigate the effects of MK-801 (0.1mg/kg) on the expression of place preference conditioned with food and morphine (5.0mg/kg) in rats. The data indicates that MK-801 potentiates the expression of food-induced conditioned place preference (CPP) but retards that of morphine CPP. It also demonstrates that the opposite effects of MK-801 on food and morphine CPP expression were caused neither by hyperactivity nor by the impairment of memory retrieval. These results suggest that MK-801 enhances food craving and inhibits morphine craving in rats, and that the roles of glutamatergic NMDA receptor mechanisms in the reward processing of natural reinforcers and addictive drugs may be dissociable.
Yonghui
Li
L
Institute of Psychology, Chinese Academy of Sciences; Laboratory of Mental Health, Chinese Academy of Sciences, P.R. China. liyonghui@psych.ac.cn
Xigeng
Zheng
Z
Yunjing
Bai
B
Xiaoyan
Yang
Y
Nan
Sui
S
D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects*; D003627:Data Interpretation, Statistical; D016291:Dizocilpine Maleate / Q000494:pharmacology*; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D005502:Food; D018698:Glutamic Acid / Q000502:physiology; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009043:Motor Activity / Q000187:drug effects; D009294:Narcotics / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012054:Reinforcement, Psychology; D012201:Reward
D018691:Excitatory Amino Acid Antagonists; D009294:Narcotics; D018698:Glutamic Acid; D016291:Dizocilpine Maleate; D009020:Morphine