Mechanisms of exercise-induced hypoalgesia. J Pain 2014 Dec;15(12):1294-1304
Date
09/28/2014Pubmed ID
25261342Pubmed Central ID
PMC4302052DOI
10.1016/j.jpain.2014.09.006Scopus ID
2-s2.0-84916216876 (requires institutional sign-in at Scopus site) 240 CitationsAbstract
UNLABELLED: The purpose of this study was to examine opioid and endocannabinoid mechanisms of exercise-induced hypoalgesia (EIH). Fifty-eight men and women (mean age = 21 years) completed 3 sessions. During the first session, participants were familiarized with the temporal summation of heat pain and pressure pain protocols. In the exercise sessions, following double-blind administration of either an opioid antagonist (50 mg naltrexone) or placebo, participants rated the intensity of heat pulses and indicated their pressure pain thresholds and pressure pain ratings before and after 3 minutes of submaximal isometric exercise. Blood was drawn before and after exercise. Results indicated that circulating concentrations of 2 endocannabinoids, N-arachidonylethanolamine and 2-arachidonoylglycerol, as well as related lipids oleoylethanolamide, palmitoylethanolamide, N-docosahexaenoylethanolamine, and 2-oleoylglycerol, increased significantly (P < .05) following exercise. Pressure pain thresholds increased significantly (P < .05), whereas pressure pain ratings decreased significantly (P < .05) following exercise. Also, temporal summation ratings were significantly lower (P < .05) following exercise. These changes in pain responses did not differ between the placebo and naltrexone conditions (P > .05). A significant association was found between EIH and docosahexaenoylethanolamine. These results suggest involvement of a nonopioid mechanism in EIH following isometric exercise.
PERSPECTIVE: Currently, the mechanisms responsible for EIH are unknown. This study provides support for a potential endocannabinoid mechanism of EIH following isometric exercise.
Author List
Koltyn KF, Brellenthin AG, Cook DB, Sehgal N, Hillard CAuthor
Cecilia J. Hillard PhD Associate Dean, Center Director, Professor in the Pharmacology and Toxicology department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AdolescentAdult
Amides
Arachidonic Acids
Cross-Over Studies
Double-Blind Method
Endocannabinoids
Ethanolamines
Exercise
Female
Glycerides
Glycine
Hot Temperature
Humans
Isometric Contraction
Male
Oleic Acids
Pain
Pain Perception
Pain Threshold
Palmitic Acids
Pressure
Young Adult
