Effects of 5,7-Dihydroxytryptamine injection in dorsal and median Raphe nuclei on Morphine dependence in rat

Abstract: Previous studies have shown that morphine addiction is caused by abnormality in neurotransmission system. Serotonin is one of the most important neurotransmitters involved in addiction. The dorsal and median raphe nuclei are the important sites that synthesize and release this neurotransmitter. In this study we have injected 5,7-dihydroxytryptamine, a serotonergic neurotoxin into the dorsal and median raphe nuclei followed of evaluation of craving behavior for morphine. Behavioral and electrophysiological studies (EEG) were conducted for the evaluation of morphine dependence. The results evaluated by self-administration method showed that, 5,7-dihydroxytryptamine increased craving for morphine in comparison with sham group. Furthermore the results of withdrawal syndrome signs showed that 5,7-dihydroxytryptamine increased dependency to morphine compared to the sham group. Electrophysiological study revealed that total power of EEG in 5,7-dihydroxytryptamine receiving group was less than the control group (P