A.A Pourshah-Nazari - Instrutor
H Ataei - Associate professor
GH.R Sepehri - Assistant professor
A Rafati - Instructor

previous studies have shown that morphine addiction is caused by abnormality in neurotransmission system.serotonin is one of the most important neurotransmiters involved in addiction.the dorsal and median raphe nuclei are the important sites that synthesize and release this neurotransmiters in this study we have injected ۵,۷  dihyroxytryptamine a serotonergic neurotoxin into the dorsal and median raphe nuclei followed of evaluation of craving behaviour for morphine.behavioural and electrophysiological studies(EEG) were conducted for the evaluation of morphine dependence.the results evaluated by self-administration method showed that,۵,۷ dihyroxytryptamine increased craving for morphine in comparison with sham group.furthermore the results of withdrawal syndrome syndrome sihns showed that ۵,۷ dihyroxytryptamine increased dependency to morphine compared to the sham group.electrophysiological study revealed that total power of EEG in ۵,۷ dihyroxytryptamine receiving group was less than the control group(p<۰.۰۵) by conclusion it seems that ۵,۷ dihyroxytryptamine can increase craving to morphine,by destroying serotonergic system.therefore in patients who must receive morphine as an analgesic,prescription of drugs that interact with serotonergic system should be avoided.

۵, ۷ DHT, raphe nucleus, morphine dependence, Rat