title: Nicotine-induced behavioral sensitization in an adult rat model of attention deficit/hyperactivity disorder (ADHD).
abstract: Attention deficit hyperactivity disorder (ADHD) is associated with increased risk of tobacco dependence. Nicotine, the main psychoactive component of tobacco, appears to be implicated in ADHD-related tobacco dependence. However, the behavioral responsiveness to nicotine of the prevalent animal model of ADHD, the spontaneously hypertensive rat (SHR), is currently underinvestigated. The present study examined the activational effects of acute and chronic nicotine on the behavior of adult male SHRs, relative to Wistar Kyoto (WKY) controls. Experiment 1 verified baseline strain differences in open-field locomotor activity. Experiment 2 tested for baseline strain differences in rotational behavior using a Rotorat apparatus. Adult SHR and WKY rats were then exposed to a 7-day regimen of 0.6mg/kg/d s.c. nicotine, or saline, prior to each assessment. A separate group of SHRs underwent similar training, but was pre-treated with mecamylamine, a cholinergic antagonist. Nicotine sensitization, context conditioning, and mecamylamine effects were then tested. Baseline strain differences were observed in open-field performance and in the number of full rotations in the Rotorat apparatus, but not in the number of 90° rotations or direction changes. In these latter measures, SHRs displayed weaker nicotine-induced rotational suppression than WKYs. Both strains expressed nicotine-induced sensitization of rotational activity, but evidence for strain differences in sensitization was ambiguous; context conditioning was not observed. Mecamylamine reversed the effects of nicotine on SHR performance. These findings are consistent with the hypothesis that a reduced aversion to nicotine (expressed in rats as robust locomotion) may facilitate smoking among adults with ADHD.
authors.affiliation: Arizona State University, Department of Psychology, P.O. Box 871104, Tempe, AZ 85287, United States.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Watterson
authors.affiliation: Arizona State University, Department of Psychology, P.O. Box 871104, Tempe, AZ 85287, United States.
authors.forename: Alexander
authors.initials: A
authors.lastname: Spitzer
authors.affiliation: Arizona State University, Department of Psychology, P.O. Box 871104, Tempe, AZ 85287, United States; Center for Substance Abuse Research Temple University School of Medicine, 3500N. Broad St., Medical Education and Research Bldg., 8th Floor, Philadelphia, PA 19140, United States.
authors.forename: Lucas R
authors.initials: LR
authors.lastname: Watterson
authors.affiliation: Arizona State University, Department of Psychology, P.O. Box 871104, Tempe, AZ 85287, United States.
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Brackney
authors.affiliation: California State University, Long Beach, CA 90840, United States.
authors.forename: Arturo R
authors.initials: AR
authors.lastname: Zavala
authors.affiliation: Arizona State University, Department of Psychology, P.O. Box 871104, Tempe, AZ 85287, United States.
authors.forename: M Foster
authors.initials: MF
authors.lastname: Olive
authors.affiliation: Arizona State University, Department of Psychology, P.O. Box 871104, Tempe, AZ 85287, United States. Electronic address: Federico.Sanabria@asu.edu.
authors.forename: Federico
authors.initials: F
authors.lastname: Sanabria
mesh_terms: D000818:Animals; D001289:Attention Deficit Disorder with Hyperactivity / Q000523:psychology*; D001522:Behavior, Animal / Q000187:drug effects; D004195:Disease Models, Animal; D008124:Locomotion / Q000187:drug effects*; D008297:Male; D008464:Mecamylamine / Q000008:administration & dosage; D009043:Motor Activity / Q000187:drug effects; D009538:Nicotine / Q000008:administration & dosage*; D018722:Nicotinic Agonists / Q000008:administration & dosage*; D018733:Nicotinic Antagonists / Q000008:administration & dosage; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY
chemical_list: D018722:Nicotinic Agonists; D018733:Nicotinic Antagonists; D008464:Mecamylamine; D009538:Nicotine
keywords: ADHD; Nicotine; Sensitization; Spontaneously hypertensive rat; Suppression; Wistar Kyoto