Chronic D1 agonist and ethanol coadministration facilitate ethanol-mediated behaviors

Pharmacol Biochem Behav. 2003 Sep;76(2):335-42. doi: 10.1016/j.pbb.2003.08.004.

Abstract

Separate lines of evidence suggest that neuroadaptations associated with ethanol (EtOH) reinforcement can be initiated by chronic EtOH preexposure and a signaling pathway activated by dopamine (DA) D1 receptor stimulation. We have previously shown that rewarding and locomotor effects of EtOH alone [Pharmacol. Biochem. Behav. 72 (2002) 787] are enhanced after chronic exposure to self-administered EtOH/cocaine combinations. To determine the importance of chronic EtOH exposure, dopamine D1 receptor activation and mode of drug administration in EtOH reward, animals were given daily intravenous infusions of experimenter-administered saline, EtOH (2.0 g/kg), the DA D1 receptor agonist, SKF81297 (0.2 mg/kg), or EtOH+SKF81297 over a 4-week period. Compared to other groups, animals preexposed to EtOH+SKF81297 self-administered significantly greater amounts of intravenous EtOH and showed greater enhancement and less suppression of locomotor activity in response to a range of intravenous EtOH dosages (0.125, 0.25, 0.5, 1.0 and 1.5 g/kg). Since chronic treatment with EtOH alone did not enhance EtOH-induced reinforcement or locomotor activity, it is unlikely that these effects were due to EtOH tolerance. These findings suggest that chronic D1 receptor activation combined with EtOH administration alters neural responsiveness to EtOH and support the notion that D1 activation is important to EtOH reward.

Publication types

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

MeSH terms

  • Animals
  • Behavior, Animal / drug effects*
  • Benzazepines / pharmacology
  • Central Nervous System Depressants / blood
  • Central Nervous System Depressants / pharmacology*
  • Conditioning, Operant / drug effects
  • Dopamine Agonists / pharmacology*
  • Dose-Response Relationship, Drug
  • Drug Synergism
  • Ethanol / blood
  • Ethanol / pharmacology*
  • Food
  • Motor Activity / drug effects
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Dopamine D1 / agonists*
  • Reinforcement, Psychology*
  • Self Administration

Substances

  • Benzazepines
  • Central Nervous System Depressants
  • Dopamine Agonists
  • Receptors, Dopamine D1
  • Ethanol
  • SK&F 81297