Bromocriptine self-administration and bromocriptine-reinstatement of cocaine-trained and heroin-trained lever pressing in rats

Psychopharmacology (Berl). 1990;100(3):355-60. doi: 10.1007/BF02244606.


Rats were trained to lever press for intravenous cocaine (1.0 mg/kg/injection) and then switched to bromocriptine (0.3, 1.0, or 3.0 mg/kg/injection) on a FR-1 reinforcement schedule. Bromocriptine sustained responding at all three doses; hourly drug intake increased linearly with log-dose. In a second experiment, animals were trained to respond for cocaine (1.0 mg/kg/injection) or heroin (0.1 mg/kg/injection) reinforcement; drug was available for the first 2 h of each daily session; saline was substituted for cocaine or heroin for 5 subsequent hours. One hour into each saline substitution session, an intravenous injection of saline or bromocriptine (0.0, 0.5, 1.0, or 2.0 mg/kg) was given. Bromocriptine reinstated both cocaine-trained and heroin-trained lever pressing; under these conditions, the drug was most effective in the heroin-trained animals. Reinforcing doses of clonidine (0.0625 and 0.125 mg/kg), methohexital, and nicotine (0.05 and 0.1 mg/kg), and a sub-intoxicating dose of ethanol (2 g/kg) failed to reinstate cocaine-trained responding. These data indicate that bromocriptine has cocaine-like and heroin-like stimulus and reinforcing effects.

MeSH terms

  • Animals
  • Bromocriptine / pharmacology*
  • Clonidine / pharmacology
  • Cocaine / pharmacology*
  • Conditioning, Operant / drug effects*
  • Ethanol / pharmacology
  • Heroin / pharmacology*
  • Male
  • Nicotine / pharmacology
  • Rats
  • Reinforcement Schedule
  • Reinforcement, Psychology
  • Self Administration


  • Bromocriptine
  • Ethanol
  • Nicotine
  • Heroin
  • Cocaine
  • Clonidine