• Home
  • Search Results
  • Delay discounting of oral morphine and sweetened juice rewards in dependent and non-dependent rats.

Delay discounting of oral morphine and sweetened juice rewards in dependent and non-dependent rats.

Psychopharmacology (2014-02-19)
Colin Harvey-Lewis, Johnna Perdrizet, Keith B J Franklin
ABSTRACT

Opioid-dependent humans are reported to show accelerated delay discounting of opioid rewards when compared to monetary rewards. It has been suggested that this may reflect a difference in discounting of consumable and non-consumable goods not specific to dependent individuals. Here, we evaluate the discounting of similar morphine and non-morphine oral rewards in dependent and non-dependent rats We first tested the analgesic and rewarding effects of our morphine solution. In a second experiment, we assigned rats randomly to either dependent or non-dependent groups that, 30 min after daily testing, received 30 mg/kg subcutaneous dose of morphine, or saline, respectively. Delay discounting of drug-free reward was examined prior to initiation of the dosing regimen. We tested discounting of the morphine reward in half the rats and retested the discounting of the drug-free reward in the other half. All tests were run 22.5 h after the daily maintenance dose. Rats preferred the morphine cocktail to the drug-free solution and consumed enough to induce significant analgesia. The control quinine solution did not produce these effects. Dependent rats discounted morphine rewards more rapidly than before dependence and when compared to discounting drug-free rewards. In non-dependent rats both reward types were discounted similarly. These results show that morphine dependence increases impulsiveness specifically towards a drug reward while morphine experience without dependence does not.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Quinine hydrochloride dihydrate
Sigma-Aldrich
Quinine hydrochloride dihydrate, tested according to Ph. Eur.
Sigma-Aldrich
Quinine hydrochloride dihydrate, BioReagent, suitable for fluorescence, ≥98.0% (NT)
Supelco
Morphine sulfate salt solution, 1.0 mg/mL in methanol, drug standard

Social Media

LinkedIn icon
Twitter icon
Facebook Icon
Instagram Icon

MilliporeSigma

Research. Development. Production.

We are a leading supplier to the global Life Science industry with solutions and services for research, biotechnology development and production, and pharmaceutical drug therapy development and production.

© 2021 Merck KGaA, Darmstadt, Germany and/or its affiliates. All Rights Reserved.

Reproduction of any materials from the site is strictly forbidden without permission.