Faculty Collaboration Database

Endocannabinoid and Opioid System Interactions in Exercise-Induced Hypoalgesia. Pain Med 2018 Jan 01;19(1):118-123

Date

04/08/2017

Pubmed ID

28387833

Pubmed Central ID

PMC6454785

DOI

10.1093/pm/pnx058

Scopus ID

2-s2.0-85041366186 (requires institutional sign-in at Scopus site)   63 Citations

Abstract

OBJECTIVE: The purpose of this study was to examine the interaction between the endogenous opioid and endocannabinoid (eCB) systems in a pain modulatory process known as exercise-induced hypoalgesia (EIH).

DESIGN: Randomized controlled trial.

SETTING: Clinical research unit in a hospital.

SUBJECTS: Fifty-eight healthy men and women (mean age = 21 ± 3 years) participated in this study.

METHODS: Participants were administered (randomized, double-blind, counterbalanced procedure) an opioid antagonist (i.e., naltrexone) and a placebo prior to performing pain testing and isometric exercise.

RESULTS: Results indicated that 2-arachidonoylglycerol (2-AG) and 2-oleoylglycerol (2-OG) increased significantly (P < 0.05) following exercise in both placebo and naltrexone conditions. In comparison, N-arachidonylethanolamine (AEA) and oleoylethanolamine (OEA) increased significantly (P < 0.05) following exercise in the placebo condition but not the naltrexone condition. There were no significant (P > 0.05) differences in palmitolethanolamine (PEA) between the placebo and naltrexone conditions.

CONCLUSIONS: As reductions in pain (i.e., EIH) were observed following both conditions, these results suggest that the opioid system may not be the primary system involved in exercise-induced hypoalgesia and that 2-AG and 2-OG could contribute to nonopioid exercise-induced hypoalgesia. Moreover, as exercise-induced increases in AEA and OEA were blocked by naltrexone pretreatment, this suggests that the opioid system may be involved in the increase of AEA and OEA following exercise.

Author List

Crombie KM, Brellenthin AG, Hillard CJ, Koltyn KF

Author

Cecilia J. Hillard PhD Associate Dean, Center Director, Professor in the Pharmacology and Toxicology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Double-Blind Method
Endocannabinoids
Exercise
Female
Humans
Male
Naltrexone
Narcotic Antagonists
Pain Perception
Pain Threshold
Young Adult