ABSTRACT
Objective To study the relation between the level of central N-methyl-D-aspartate (NMDA) receptor system and the degree of morphine withdrawal syndrome in rats. Methods We established the morphine-dependence model in rats,stimulated addiction by naloxone after intracerebroventricular injection of glutamic acid/ketamine/MK-801,and then observed the effects on rats' morphine withdrawal syndrome. Results Glutamic acid significantly raised the behavior scores of teeth chattering,wet shakes,writhing,penis licking and weight loss,while ketamine and MK-801 decreased the scores. Conclusion Changes of central NMDA system obviously affect morphine withdrawal syndrome in rats,which may be useful laboratory evidence in selecting new no-opiod therapeutic medicine for morphine resistance and addiction.