title: Effect of electrical stimulation of nucleus accumbens with low, median and high currents intensities on conditioned place preference induced by morphine in rats.
abstract: BACKGROUND
  Some investigators indicated the effect of electrical or chemical stimulation on different parts of the brain and its effect on animal's behaviors. Furthermore, drug addiction is known to be associated with dysfunction of memory and motivational systems. In this study, we aimed to evaluate the effect of electrical stimulation of nucleus accumbens (NAc) with different currents intensities on conditioned place preference (CPP) induced by morphine.
  
  
  METHODS
  Male Wistar rats were randomly divided for experimental groups (n = 8). We investigated the influence of electrical stimulation with different current intensities (low: 15 μA, median: 50 μA and high: 100 μA) on NAc with ineffective and effective dose of morphine (0.5 and 5 mg/kg, respectively) on acquisition and expression of morphine-induced place conditioning in male rats.
  
  
  RESULTS
  The doses of subcutaneous administration morphine (2.5 and 5 mg/kg, P < 0.05 and P < 0.001; respectively) induced CPP compared with saline group. Furthermore, our findings are showed that electrical stimulation (100 μA) of NAc suppressed morphine-induced CPP. It revealed impairment of learning and memory formation in conditioning process due to morphine administration.
  
  
  CONCLUSIONS
  It is possible that high current intensity (100 μA) had an accompanied effect by a reversal of the increased tissue contents of dopamine and its metabolites in the NAc of morphine-induced CPP rats. Furthermore, high current intensity in combination with ineffective dose of morphine (0.5 mg/kg) increased morphine-induced CPP probability via the prove reward system.
authors.affiliation: Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Radahmadi
authors.affiliation: Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Effat
authors.initials: E
authors.lastname: Ramshini
authors.affiliation: Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Nasrin
authors.initials: N
authors.lastname: Hosseini
authors.affiliation: Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Sara
authors.initials: S
authors.lastname: Karimi
authors.affiliation: Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Hojjatallah
authors.initials: H
authors.lastname: Alaei
keywords: Conditioned place preference; electrical stimulation; morphine; rat