title: Influence of experimental history on nicotine self-administration in squirrel monkeys.
abstract: Methods for establishing robust long-term self-administration of intravenous (i.v.) nicotine, the primary psychoactive agent in tobacco, are not well-established in laboratory animals.
  
  
  
  Here, we examine the use of a fading procedure to establish robust and consistent i.v. nicotine self-administration under second-order schedule conditions in squirrel monkeys.
  
  
  
  First, self-administration behavior was developed in two groups of male squirrel monkeys using a second-order fixed-interval 5-min schedule with fixed-ratio 5 units (FI 5-min (FR5: S)). Comparable performances were maintained by i.v. cocaine (0.032 mg/kg/injection (inj); group A, n = 3) and the combination of food delivery (20-30 % condensed milk) and 0.01 mg/kg/inj i.v. nicotine (group B, n = 3). Subsequently, the concentration of condensed milk was gradually reduced to zero in the second group and self-administration behavior was maintained by i.v. nicotine alone. Next, self-administration of a range of doses of i.v. nicotine (0.001-0.032 mg/kg/inj) and, in additional experiments, the minor tobacco alkaloid anatabine (0.01-0.18 mg/kg/inj) was studied in both groups.
  
  
  
  Results show that nicotine and anatabine had reinforcing effects in both groups. However, optimal doses of nicotine and anatabine maintained significantly higher rates of i.v. self-administration behavior in subjects trained with the fading procedure than in subjects provided with a history of cocaine-maintained responding.
  
  
  
  These results illustrate conditions under which robust i.v. nicotine self-administration can be established in squirrel monkeys and the influence of prior experimental history in the expression of reinforcing effects of nicotine and anatabine.
authors.affiliation: Preclinical Pharmacology Laboratory, McLean Hospital/Harvard Medical School, 115 Mill Street, Belmont, MA, 02478, USA. rdesai@mclean.harvard.edu.
authors.forename: Rajeev I
authors.initials: RI
authors.lastname: Desai
authors.affiliation: Preclinical Pharmacology Laboratory, McLean Hospital/Harvard Medical School, 115 Mill Street, Belmont, MA, 02478, USA.
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Sullivan
authors.affiliation: Preclinical Pharmacology Laboratory, McLean Hospital/Harvard Medical School, 115 Mill Street, Belmont, MA, 02478, USA.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Kohut
authors.affiliation: Preclinical Pharmacology Laboratory, McLean Hospital/Harvard Medical School, 115 Mill Street, Belmont, MA, 02478, USA.
authors.forename: Jack
authors.initials: J
authors.lastname: Bergman
mesh_terms: D000470:Alkaloids / Q000008:administration & dosage; D000818:Animals; D016739:Behavior, Addictive / Q000523:psychology*; D001522:Behavior, Animal / Q000187:drug effects* / Q000502:physiology; D003042:Cocaine / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D004435:Eating / Q000187:drug effects / Q000502:physiology / Q000523:psychology; D008297:Male; D009538:Nicotine / Q000008:administration & dosage*; D011725:Pyridines / Q000008:administration & dosage; D012054:Reinforcement, Psychology; D012453:Saimiri; D012646:Self Administration
chemical_list: D000470:Alkaloids; D011725:Pyridines; C012737:anatabine; D009538:Nicotine; D003042:Cocaine
keywords: Anatabine; Cocaine; Experimental history; Minor tobacco alkaloid; Nicotine; Nonhuman primates; Self-administration