Journal article
THC-methadone and THC-naltrexone interactions on discrimination, antinociception, and locomotion in rats
Behavioural pharmacology, Vol.22(5-6), pp.489-497
09/2011
Handle:
https://hdl.handle.net/2376/116559
PMID: 21716095
Abstract
This study examined cannabinoid-opioid interactions within the same subjects on measures of discrimination, antinociception, horizontal locomotion, and catalepsy. Male Sprague-Dawley rats were trained to discriminate Δ(9)-tetrahydrocannabinol (THC, 3 mg/kg) from vehicle. THC alone (0.32-10 mg/kg) dose-dependently increased THC-appropriate lever responding and decreased response rate. THC alone also produced paw pressure antinociception and decreased locomotor activity, but did not produce catalepsy. Methadone (0.32-5.6 mg/kg) and naltrexone (0.32-3.2 mg/kg) alone produced low THC-appropriate lever responding up to doses that decreased response rate. When combined with THC, methadone (1.0 mg/kg) flattened the THC discrimination curve, but did not affect antinociceptive or motoric effects of THC. Naltrexone did not alter any effects of THC. In rats that were not trained to discriminate THC from vehicle, 1.0 mg/kg methadone did enhance THC antinociception. These results suggest that μ-opioid receptor agonists can disrupt the discriminative stimulus effects of cannabinoids while not significantly altering their antinociceptive or motoric effects, in chronically drug-exposed subjects. Further research is required to determine whether opioid enhancement of cannabinoid antinociception is limited to acute exposure, or simply requires higher doses in chronically drug-exposed subjects.
Metrics
7 Record Views
Details
- Title
- THC-methadone and THC-naltrexone interactions on discrimination, antinociception, and locomotion in rats
- Creators
- Alexa A Wakley - Department of Psychology, Washington State University, Pullman, Washington 99164-4820, USA. awakley@wsu.eduRebecca M Craft
- Publication Details
- Behavioural pharmacology, Vol.22(5-6), pp.489-497
- Academic Unit
- Psychology, Department of
- Publisher
- England
- Identifiers
- 99900547991901842
- Language
- English
- Resource Type
- Journal article