title: Effects of the specific α4β2 nAChR antagonist, 2-fluoro-3-(4-nitrophenyl) deschloroepibatidine, on nicotine reward-related behaviors in rats and mice.
abstract: BACKGROUND
  Alleviating addiction to tobacco products could prevent millions of deaths. Investigating novel compounds selectively targeting α4β2 nAChRs hypothesized to have a key role in the rewarding effects of nicotine may be a useful approach for future treatment.
  
  
  OBJECTIVE
  The present study was designed to evaluate 2-fluoro-3-(4-nitrophenyl) deschloroepibatidine (4-nitro-PFEB), a potent competitive antagonist of neuronal α4β2 nAChRs, in several animal models related to nicotine reward: drug discrimination, intracranial self-stimulation (ICSS), conditioned place preference, and limited access to self-administration.
  
  
  METHODS
  Long Evans rats were trained in a two-lever discrimination procedure to discriminate 0.4 mg/kg nicotine (s.c.) from saline. Male Sprague-Dawley rats were stereotaxically implanted with electrodes and trained to respond for direct electrical stimulation of the medial forebrain bundle. ICR mice were evaluated using an unbiased place preference paradigm, and finally, male Wistar rats were implanted with intrajugular catheters and tested for nicotine self-administration under limited access (1 h/day).
  
  
  RESULTS
  4-Nitro-PFEB attenuated the discriminative stimulus effects of nicotine, but alone did not produce nicotine-like discriminative stimulus effects. Nicotine-induced facilitation of ICSS reward thresholds was reversed by 4-nitro-PFEB, which alone had no effect on thresholds. 4-Nitro-PFEB also blocked the conditioned place preference produced by nicotine, but alone had no effect on conditioned place preference. Finally, 4-nitro-PFEB dose-dependently decreased nicotine self-administration.
  
  
  CONCLUSIONS
  These results support the hypothesis that neuronal α4β2 nAChRs play a key role in mediating the rewarding effects of nicotine and further suggest that targeting α4β2 nAChRs may yield a potential candidate for the treatment of nicotine dependence.
authors.affiliation: Department of Pharmacology and Toxicology, Virginia Commonwealth University, 1217 E Marshall St., PO Box 980613, Richmond, VA 23298-0613, USA.
authors.forename: K M
authors.initials: KM
authors.lastname: Tobey
authors.forename: D M
authors.initials: DM
authors.lastname: Walentiny
authors.forename: J L
authors.initials: JL
authors.lastname: Wiley
authors.forename: F I
authors.initials: FI
authors.lastname: Carroll
authors.forename: M I
authors.initials: MI
authors.lastname: Damaj
authors.forename: M R
authors.initials: MR
authors.lastname: Azar
authors.forename: G F
authors.initials: GF
authors.lastname: Koob
authors.forename: O
authors.initials: O
authors.lastname: George
authors.forename: L S
authors.initials: LS
authors.lastname: Harris
authors.forename: R E
authors.initials: RE
authors.lastname: Vann
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D003216:Conditioning, Operant / Q000187:drug effects; D004192:Discrimination, Psychological / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D015394:Molecular Structure; D009538:Nicotine / Q000008:administration & dosage*; D018733:Nicotinic Antagonists / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D011725:Pyridines / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats; D020318:Rats, Long-Evans; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D011978:Receptors, Nicotinic / Q000378:metabolism*; D012201:Reward; D012646:Self Administration; D012653:Self Stimulation / Q000187:drug effects; D013045:Species Specificity
chemical_list: C511623:2-fluoro-3-(4-nitrophenyl)deschloroepibatidine; D019086:Bridged Bicyclo Compounds, Heterocyclic; D018733:Nicotinic Antagonists; D011725:Pyridines; D011978:Receptors, Nicotinic; C403531:nicotinic receptor alpha4beta2; D009538:Nicotine