title: Microinfusion of bupropion inhibits putative GABAergic neuronal activity of the ventral tegmental area.
abstract: BACKGROUND
  The most common interpretation for the mechanisms of antidepression is the increase of the brain monoamine levels such as dopamine (DA). The increase of DA can reduce depression but it can also decrease the monoamine release because of autoreceptor inhibition. Although bupropion can decrease the dopamine release, there is evidence about stimulatory effects of chronic application of bupropion on ventral tegmental area (VTA) neurons. In this study, the intra-VTA acute microinfusion of bupropion on putative VTA non-Dopaminergic (VTA-nonDA) neuronal firing rates was evaluated by a single neuron recording technique.
  
  
  METHODS
  Animals were divided into 7 groups (sham, and 6 bupropion-microinfused groups with 1, 10(-1), 10(-2), 10(-3), 10(-4), and 10(-5) mol, 1 µl/3 min, intra-VTA). A single neuron recording technique was done according to the stereotaxic coordination. After 10 min baseline recording, ACSF or bupropion was microinfused. The recording continued to recovery period in the treated groups. The prestimulus time (PST) and interspike interval (ISI) histograms were calculated for every single unit. The assessment of the drug effect was carried out by one-way analysis of variance (ANOVA) and Post-hoc test.
  
  
  RESULTS
  126 non-DA neurons were separated. Bupropion could inhibit 116 neurons and 11 neurons had no significant response. Maximum inhibition was 79.1% of baseline firing rate with 44.3 min duration. The inhibitory effect of bupropion was dose-dependent.
  
  
  CONCLUSIONS
  The acute inhibitory effects of bupropion on VTA-nonDA neurons can explain the fast inhibitory effects of bupropion and other antidepressants on the VTA. These data can explain some side effects of antidepressants.
authors.affiliation: Department of Physiology, Faculty of Medicine, Urmia University of Medical Sciences, Urmia, Iran.
authors.forename: Sanaz
authors.initials: S
authors.lastname: Amirabadi
authors.affiliation: Department of Physiology, Faculty of Medicine, Urmia University of Medical Sciences, Urmia, Iran ; Neurophysiology Research Center, Urmia University of Medical Sciences, Urmia, Iran.
authors.forename: Firouz Ghaderi
authors.initials: FG
authors.lastname: Pakdel
authors.affiliation: Neuroscience Research Center, Department of Physiology, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Parviz
authors.initials: P
authors.lastname: Shahabi
authors.affiliation: Danesh Pey Hadi Co., Faculty of Medicine, Urmia University of Medical Sciences, Urmia, Iran.
authors.forename: Somayyeh
authors.initials: S
authors.lastname: Naderi
authors.affiliation: Danesh Pey Hadi Co., Faculty of Medicine, Urmia University of Medical Sciences, Urmia, Iran ; Department of Histology & Embryology, School of Medicine, Dokuz Eylol University, Izmir, Turkey.
authors.forename: Mostafa Ashrafi
authors.initials: MA
authors.lastname: Osalou
authors.affiliation: Department of Histology & Embryology, School of Medicine, Dokuz Eylol University, Izmir, Turkey.
authors.forename: Ulker
authors.initials: U
authors.lastname: Cankurt
keywords: Antidepressant; Bupropion; Putative GABAergic; Rat; Ventral Tegmental Area; non-Dopaminergic