Dopaminergic mechanism for caffeine-produced cocaine seeking in rats

Neuropsychopharmacology. 2002 Apr;26(4):422-30. doi: 10.1016/S0893-133X(01)00343-8.

Abstract

Systemic administration of caffeine reinstates extinguished cocaine self-administration behavior in rats, but the mechanism mediating this behavioral effect has not been established. The present study examined the role of adenosinergic A2 and dopaminergic mechanisms in caffeine-produced cocaine seeking. Following extinction of cocaine self-administration, experimenter-administered injections of caffeine (1.25-20 mg/kg) and theophylline (1-10 mg/kg) dose-dependently reinstated extinguished cocaine-seeking behavior. Administration of the adenosinergic A2 antagonist, 3,7-dimethyl-1-propargylxanthine (DMPX; 0.546-2.18 microg/kg), failed to produce cocaine seeking. Pretreatment with doses of the adenosine A1/A2 agonist 5'-N-ethylcarboxamidoadenosine (NECA; 0.003-0.03 mg/kg) that were below those that produced marked sedation failed to block reinstatement. These data suggest that methylxanthine-produced cocaine seeking is not due to adenosine A2 receptor antagonism. In contrast, pretreatment with the dopaminergic D1-like antagonist SCH 23390 (0.005-0.02 mg/kg) or the D2-like antagonist eticlopride (0.03-0.3 mg/kg) produced a dose-dependent attenuation of caffeine-produced reinstatement at doses that did not decrease cocaine self-administration. These findings suggest that dopaminergic mechanisms underlie the ability of caffeine to reinstate extinguished cocaine-taking behavior.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenosine / antagonists & inhibitors
  • Adenosine / physiology
  • Adenosine-5'-(N-ethylcarboxamide) / pharmacology
  • Animals
  • Benzazepines / pharmacology
  • Caffeine / pharmacology*
  • Central Nervous System Stimulants / pharmacology*
  • Cocaine-Related Disorders / psychology*
  • Conditioning, Operant / drug effects
  • Dopamine / physiology*
  • Dopamine Antagonists / pharmacology
  • Dose-Response Relationship, Drug
  • Male
  • Motor Activity / drug effects
  • Purinergic P1 Receptor Antagonists
  • Rats
  • Rats, Sprague-Dawley
  • Reinforcement Schedule
  • Salicylamides / pharmacology
  • Self Administration
  • Theophylline / pharmacology
  • Vasodilator Agents / pharmacology

Substances

  • Benzazepines
  • Central Nervous System Stimulants
  • Dopamine Antagonists
  • Purinergic P1 Receptor Antagonists
  • Salicylamides
  • Vasodilator Agents
  • Adenosine-5'-(N-ethylcarboxamide)
  • Caffeine
  • Theophylline
  • eticlopride
  • Adenosine
  • Dopamine