title: Effects of Temporary Inactivation and Electrical Stimulation of the Dorsal Raphe Nucleus on Morphine-induced Conditioned Place Preference.
abstract: BACKGROUND
  The dorsal raphe nucleus (DRN) influences a wide range of behavioral and reward function. In this study, we evaluated electrical stimulation and inactivation of DRN on morphine conditioned place preference (CPP).
  
  
  METHODS
  The rats were anesthetised (n = 7 for each group) and the electrode and cannula were implanted into the DRN by stereotaxic instrument. Electrical stimulation (100μA) and reversible inactivation by lidocaine were induced into DRN and then morphine-induced CPP was investigated.
  
  
  RESULTS
  The stimulation of DRN in combination with effective dose of morphine showed a significant decrease only on expression phases 20s (SD 33.7) when compared with morphine group 119.85s (SD 23.7) (One way ANOVA, Tukey's; P = 0.036). Also, this stimulation in combination with ineffective dose of morphine showed a significant increase only on acquisition phases 67.5s (SD 41.2) of CPP compared with morphine group -46s (SD 18.51) (P = 0.034). Also, there were not significant differences in inactivation of DRN by lidocaine on different phase of CPP (P = 0.091) CONCLUSION: It is possible that electrical stimulation of the DRN with changes in concentration of serotonin or involving other transmitters such as glutamate and gamma amino butyric acid (GABA) would be involved to these changes of CPP.
authors.affiliation: Department of Physiology, Faculty of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran, postal code: 81746-73461.
authors.forename: Gholam Reza
authors.initials: GR
authors.lastname: Ghavipanjeh
authors.affiliation: Department of Physiology, Faculty of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran, postal code: 81746-73461.
authors.forename: Ali Asghar
authors.initials: AA
authors.lastname: Pourshanazari
authors.affiliation: Department of Physiology, Faculty of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran, postal code: 81746-73461.
authors.forename: Hojjatllah
authors.initials: H
authors.lastname: Alaei
authors.affiliation: Department of Physiology, Faculty of Sciences, Payamnoor Isfahan University, Isfahan, Iran, postal code: 81395-671.
authors.forename: Sara
authors.initials: S
authors.lastname: Karimi
authors.affiliation: Department of Physiology, Faculty of Sciences, Payamnoor Isfahan University, Isfahan, Iran, postal code: 81395-671.
authors.forename: Meghdad Abarghouei
authors.initials: MA
authors.lastname: Nejad
keywords: Lidocaine; conditioned place; dorsal raphe nucleus; electrical stimulation; morphine; rat