title: Strain dependency of the effects of nicotine and mecamylamine in a rat model of attention.
abstract: BACKGROUND
  Processes of attention have a heritable component, suggesting that genetic predispositions may predict variability in the response to attention-enhancing drugs. Among lead compounds with attention-enhancing properties are nicotinic acetylcholine receptor (nAChR) agonists.
  
  
  OBJECTIVE
  This study aims to test, by comparing three rat strains, whether genotype may influence the sensitivity to nicotine in the 5-choice serial reaction time task (5-CSRTT), a rodent model of attention.
  
  
  METHODS
  Strains tested were Long Evans (LE), Sprague Dawley (SD), and Wistar rats. The 5-CSRTT requires responses to light stimuli presented randomly in one of five locations. The effect of interest was an increased percentage of responses in the correct location (accuracy), the strongest indicator of improved attention.
  
  
  RESULTS
  Nicotine (0.05-0.2 mg/kg s.c.) reduced omission errors and response latency and increased anticipatory responding in all strains. In contrast, nicotine dose-dependently increased accuracy in Wistar rats only. The nAChR antagonist mecamylamine (0.75-3 mg/kg s.c.) increased omissions, slowed responses, and reduced anticipatory responding in all strains. There were no effects on accuracy, which was surprising giving the clear improvement with nicotine in the Wistar group.
  
  
  CONCLUSIONS
  The findings suggest strain differences in the attention-enhancing effects of nicotine, which would indicate that genetic predispositions predict variability in the efficacy of nAChR compounds for enhancing attention. The absence of effect of mecamylamine on response accuracy may suggest a contribution of nAChR desensitization to the attention-enhancing effects of nicotine.
authors.affiliation: University of Maryland School of Medicine, Maryland Psychiatric Research Center, P.O. Box 21247, Baltimore, MD, 21228, USA. bhahn@mprc.umaryland.edu.
authors.forename: Britta
authors.initials: B
authors.lastname: Hahn
authors.affiliation: University of Maryland School of Medicine, Maryland Psychiatric Research Center, P.O. Box 21247, Baltimore, MD, 21228, USA.
authors.forename: Katelyn E
authors.initials: KE
authors.lastname: Riegger
authors.affiliation: University of Maryland School of Medicine, Maryland Psychiatric Research Center, P.O. Box 21247, Baltimore, MD, 21228, USA.
authors.forename: Greg I
authors.initials: GI
authors.lastname: Elmer
mesh_terms: D000818:Animals; D001288:Attention / Q000187:drug effects* / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D008297:Male; D008464:Mecamylamine / Q000494:pharmacology*; D009538:Nicotine / Q000494:pharmacology*; D018722:Nicotinic Agonists / Q000494:pharmacology*; D018733:Nicotinic Antagonists / Q000494:pharmacology*; D051381:Rats; D020318:Rats, Long-Evans; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D011978:Receptors, Nicotinic / Q000502:physiology; D013045:Species Specificity
chemical_list: D018722:Nicotinic Agonists; D018733:Nicotinic Antagonists; D011978:Receptors, Nicotinic; D008464:Mecamylamine; D009538:Nicotine
keywords: 5-Choice serial reaction time; Attention; Genetic; Mecamylamine; Nicotine; Nicotinic; Rat; Strain