title: An intravenous self-administration procedure for assessing the reinforcing effects of hallucinogens in nonhuman primates.
abstract: BACKGROUND
  Self-administration procedures are the gold standard for investigating the reinforcing effects of drugs. The notable exception to good correspondence between laboratory self-administration studies and human drug taking behavior has historically been the classic hallucinogens.
  
  
  METHODS
  The present study used a well-established daily access procedure, followed by a novel intermittent access procedure, to investigate the reinforcing effects of LSD in baboons.
  
  
  RESULTS
  Rates of self-injection in the daily access procedure were minimal. One baboon self-administered 0.001mg/kg and a second baboon self-administered 0.0032mg/kg above vehicle levels, though rates of self-injection were clearly low and neither of the two remaining baboons self-administered any LSD dose tested in the daily access procedure. Rates of self-injection using an intermittent access procedure with discriminative stimuli resulted in two doses of LSD being self-administered above vehicle levels in two of three baboons tested (0.01 and 0.032mg/kg in one baboon; 0.0032 and 0.01mg/kg in a second). In addition, the number of self-injections at these doses was higher (range=3-6 injections) in the intermittent access procedure than in the daily access procedure (range=1-2 injections).
  
  
  CONCLUSIONS
  The present study is the first to demonstrate LSD self-administration in a laboratory animal, and though the results are limited, they indicate intermittent access procedures with discriminative stimuli may provide a reliable and valid method for investigating the reinforcing effects of IV self-administered hallucinogens in laboratory animals. The usefulness of such procedures should be further evaluated in a larger number of subjects.
authors.affiliation: Division of Neurotoxicology, National Center for Toxicological Research, US Food & Drug Administration, United States; Department of Psychiatry and Behavioral Sciences, Division of Behavioral Biology, Johns Hopkins University School of Medicine, United States. Electronic address: Amy.Goodwin@FDA.HHS.GOV.
authors.forename: Amy K
authors.initials: AK
authors.lastname: Goodwin
mesh_terms: D000818:Animals; D016739:Behavior, Addictive / Q000523:psychology*; D003216:Conditioning, Operant / Q000187:drug effects*; D006213:Hallucinogens / Q000008:administration & dosage*; D007275:Injections, Intravenous; D008238:Lysergic Acid Diethylamide / Q000008:administration & dosage*; D048529:Papio hamadryas; D012055:Reinforcement Schedule; D012054:Reinforcement, Psychology; D012646:Self Administration
chemical_list: D006213:Hallucinogens; D008238:Lysergic Acid Diethylamide
keywords: Abuse liability; Hallucinogen; Intravenous (IV) self-administration; Lysergic acid diethylamide (LSD); Operant behavior; Reinforcing effects