title: Nicotine-induced impulsive action: sensitization and attenuation by mecamylamine.
abstract: A conjunctive variable-interval differential-reinforcement-of-low-rate (VI-DRL, n=18) responding schedule and a stop-signal task (n=18) were used to evaluate the disinhibiting effects of nicotine on response withholding in rats. Sucrose solution was used to reinforce responding, and after a stable baseline was achieved under saline-administration conditions, 0.3 mg/kg nicotine was delivered before each session. Experiment 1 showed that repeated, but not the initial, administration of nicotine decreased performance on both tasks, and the effect of sensitization followed a similar timeline; 10 consecutive doses resulted in poorer proportion-correct VI-DRL trials and percent correct stop trials than the initial dose of nicotine. Furthermore, sensitization to 0.3 mg/kg nicotine decreased performance regardless of whether a spaced or consecutive-dosing regimen was followed. Experiment 2 was designed to test whether mecamylamine hydrochloride (0.1-1.0 mg/kg) could attenuate the effects of repeated 0.3 mg/kg nicotine administration, and the degree to which mecamylamine attenuation of the effect of nicotine to produce impulsive action was relative to dose. Results from experiment 2 showed that response disinhibition, as evaluated using the VI-DRL and stop-signal tasks, is related in a systematic manner to nicotinic-acetylcholine receptor activation.
authors: Saint Michael's College, Krikstone Lab for the Behavioral Sciences, Colchester, Vermont 05443, USA. akirshenbaum@smcvt.edu
authors: Ari P
authors: AP
authors: Kirshenbaum
authors: Eric R
authors: ER
authors: Jackson
authors: Seth J
authors: SJ
authors: Brown
authors: Jason R
authors: JR
authors: Fuchs
authors: Betsie C
authors: BC
authors: Miltner
authors: Adam H
authors: AH
authors: Doughty
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D007175:Impulsive Behavior / Q000139:chemically induced*; D008297:Male; D008464:Mecamylamine / Q000494:pharmacology*; D009538:Nicotine / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012055:Reinforcement Schedule
chemical_list: D008464:Mecamylamine; D009538:Nicotine