Psychopharmacology

, Volume 115, Issue 4, pp 454–462

Reversal of stress-induced anhedonia by the dopamine receptor agonist, pramipexole

  • Paul Willner
  • Spiros Lappas
  • Survjit Cheeta
  • Richard Muscat
Original Investigations

DOI: 10.1007/BF02245568

Cite this article as:
Willner, P., Lappas, S., Cheeta, S. et al. Psychopharmacology (1994) 115: 454. doi:10.1007/BF02245568

Abstract

Chronic exposure to mild unpredictable stress has previously been found to depress the consumption of a palatable (1%) sucrose solution, and to attenuate food-induced place preference conditioning. In this study the effects of pramipexole (SND-919), a dopamine D2 agonist, were studied during 7–9 weeks of chronic treatment. Pramipexole (1.0 mg/kg per day) reversed the suppression of sucrose intake in stressed animals, increasing sucrose intakes above the levels seen in untreated nonstressed controls. Pramipexole also increased sucrose intake in nonstressed animals; these effects were accompanied by increases in water intake and tended to correlate with weight loss. Drug-treated stressed animals also lost weight, but in this case water intake was unaffected. A second group of animals received a higher dose of pramipexole (2.0 mg/kg per day). The effects of the two doses were very similar. After three weeks of treatment, these animals were switched to a lower dose of pramipexole (0.1 mg/kg per day). Increases in sucrose intake were maintained over three weeks of treatment at the lower dose, with significant recovery of body weight. Two further groups received the same doses of pramipexole (1.0 mg/kg for 6 weeks or 2.0 mg/kg for 3 weeks followed by 0.1 mg/kg thereafter), but received intermittent (twice-weekly) drug treatment. Intermittent pramipexole treatments also tended to increase sucrose intakes, but the results were less consistent from week to week. Following 6–8 weeks of pramipexole treatment, food-induced place preference conditioning was studied in all animals. Untreated stressed animals showed no evidence of place conditioning. Normal conditioning was seen in both groups of stressed animals treated daily with pramipexole (at 1.0 and 0.1 mg/kg) and in the group treated twice weekly at the higher dose (1.0 mg/kg); intermittent treatment at the lower dose (0.1 mg/kg) was ineffective. The results indicate that pramipexole exerts rapid anti-anhedonic effects in the chronic mild stress model. This conclusion is complicated, but not undermined, by drug-induced weight loss and by the presence of significant drug effects in nonstressed control animals.

Key words

StressSucrose drinkingPlace preference conditioningRewardPramipexoleD2 agonistRats

Copyright information

© Springer-Verlag 1994

Authors and Affiliations

  • Paul Willner
    • 1
  • Spiros Lappas
    • 1
  • Survjit Cheeta
    • 1
  • Richard Muscat
    • 1
  1. 1.Department of PsychologyCity of London PolytechnicLondonUK
  2. 2.Dept of PsychologyUniversity of Wales, SwanseaSwanseaUK
  3. 3.Dept of Biomedical SciencesUniversity of MaltaMsidaMalta