The influence of electrical stimulation on dorsal raphe nucleus with different current intensities on morphine-induced conditioned place preference in male rats.
INTRODUCTION
The dorsal raphe nucleus (DRN) influences a wide range of behavioral and physiological processes. The purpose of the present study was to test the effects of electrical stimulation of the DRN with different current intensities on morphine-induced conditioned place preference (CPP).


MATERIALS AND METHODS
Male Wistar rats were divided for experimental groups (n=7). Stimulating electrodes were stereotaxically implanted into the DRN in anesthetized rats. We investigated the influences of electrical stimulation of the DRN with different current intensities with ineffective and effective dose of morphine (0.5 and 2.5mg/kg, respectively) on morphine-induced CPP.


RESULT
Subcutaneous administration of morphine 2.5mg/kg produced significant CPP in comparison with saline group. The stimulation of the DRN with different current intensities (10, 25, 50 and 100μA) in combination with an effective dose of morphine did not show significant differences on acquisition phases, whereas there were significant decreases on expression phases versus to the morphine group on CPP only in current intensity 100μA. The stimulation of the DRN with different current intensities in combination with an ineffective dose of morphine showed significant increases in current intensities (50 and 100μA) on acquisition phases of CPP, but did not show significant differences on expression phases versus to the morphine group on CPP.


CONCLUSION
It is possible that electrical stimulation of the DRN with changes in concentration of serotonin or involving other transmitters such as glutamate and GABA would be involved with these changes of CPP.
['Ghavipanjeh|Gholam Reza|GR|', 'Pourshanazari|Ali Asghar|AA|', 'Alaei|Hojjatllah|H|', 'Karimi|Sara|S|']
D000818:Animals D003216:Conditioning, Operant D065847:Dorsal Raphe Nucleus D004305:Dose-Response Relationship, Drug D004558:Electric Stimulation D004567:Electrodes, Implanted D007279:Injections, Subcutaneous D008297:Male D009020:Morphine D009043:Motor Activity D009294:Narcotics D051381:Rats D017208:Rats, Wistar D013238:Stereotaxic Techniques
Electrical stimulation Conditioned place preference Rat DRN Morphine