title: Levamisole enhances the rewarding and locomotor-activating effects of cocaine in rats.
abstract: BACKGROUND
  The Drug Enforcement Agency estimates that 80% of cocaine seized in the United States contains the veterinary pharmaceutical levamisole (LVM). One problem with LVM is that it is producing life-threatening neutropenia in an alarming number of cocaine abusers. The neuropharmacological profile of LVM is also suggestive of an agent with modest reinforcing and stimulant effects that could enhance cocaine's addictive effects.
  
  
  METHODS
  We tested the hypothesis that LVM (ip) enhances the rewarding and locomotor stimulant effects of cocaine (ip) using rat conditioned place preference (CPP) and locomotor assays. Effects of LVM by itself were also tested.
  
  
  RESULTS
  LVM (0-10 mg/kg) produced CPP at 1mg/kg (P<0.05) and locomotor activation at 5mg/kg (P < 0.05). For CPP combination experiments, a statistically inactive dose of LVM (0.1 mg/kg) was administered with a low dose of cocaine (2.5 mg/kg). Neither agent produced CPP compared to saline (P > 0.05); however, the combination of LVM and cocaine produced enhanced CPP compared to saline or either drug by itself (P < 0.01). For locomotor experiments, the same inactive dose of LVM (0.1mg/kg, ip) was administered with low (10 mg/kg) and high doses (30 mg/kg) of cocaine. LVM (0.1 mg/kg) enhanced locomotor activation produced by 10mg/kg of cocaine (P < 0.05) but not by 30 mg/kg (P>0.05).
  
  
  CONCLUSIONS
  LVM can enhance rewarding and locomotor-activating effects of low doses of cocaine in rats while possessing modest activity of its own.
authors: Center for Substance Abuse Research, Temple University School of Medicine, Philadelphia, PA, USA; Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA, USA.
authors: Christopher S
authors: CS
authors: Tallarida
authors: Center for Substance Abuse Research, Temple University School of Medicine, Philadelphia, PA, USA; Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA, USA.
authors: Ronald J
authors: RJ
authors: Tallarida
authors: Center for Substance Abuse Research, Temple University School of Medicine, Philadelphia, PA, USA; Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA, USA. Electronic address: scott.rawls@temple.edu.
authors: Scott M
authors: SM
authors: Rawls
mesh_terms: D000818:Animals; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D003042:Cocaine / Q000494:pharmacology*; D003216:Conditioning, Operant / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D007978:Levamisole / Q000494:pharmacology*; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012201:Reward
chemical_list: D000697:Central Nervous System Stimulants; D007978:Levamisole; D003042:Cocaine
keywords: Addiction; Cocaine; Conditioned place preference; Levamisole; Locomotor; Psychostimulant