title: Palmitoylethanolamide and stearoylethanolamide levels in the interstitium of the trapezius muscle of women with chronic widespread pain and chronic neck-shoulder pain correlate with pain intensity and sensitivity.
abstract: Chronic widespread pain (CWP) is a complex condition characterized by central hyperexcitability and altered descending control of nociception. However, nociceptive input from deep tissues is suggested to be an important drive. N-Acylethanolamines (NAEs) are endogenous lipid mediators involved in regulation of inflammation and pain. Previously we have reported elevated levels of the 2 NAEs, the peroxisome proliferator-activated receptor type-α ligand N-palmitoylethanolamine (PEA) and N-stearoylethanolamine (SEA) in chronic neck/shoulder pain (CNSP). In the present study, the levels of PEA and SEA in women with CWP (n=18), CNSP (n=34) and healthy controls (CON, n=24) were investigated. All subjects went through clinical examination, pressure pain threshold measurements and induction of experimental pain in the tibialis anterior muscle. Microdialysis dialysate of the trapezius was collected before and after subjects performed a repetitive low-force exercise and analyzed by mass spectrometry. The levels of PEA and SEA in CNSP were significantly higher post exercise compared with CWP, and both pre and post exercise compared with CON. Levels of both NAEs decreased significantly pre to post exercise in CWP. Intercorrelations existed between aspects of pain intensity and sensitivity and the level of the 2 NAEs in CWP and CNSP. This is the first study demonstrating that CNSP and CWP differ in levels of NAEs in response to a low-force exercise which induces pain. Increases in pain intensity as a consequence of low-force exercise were associated with low levels of PEA and SEA in CNSP and CWP. These results indicate that PEA and SEA have antinociceptive roles in humans.
authors.affiliation: Rehabilitation Medicine, Department of Medicine and Health Sciences, Linköping University, SE 581 85 Linköping, Sweden Pain and Rehabilitation Centre, UHL, County Council of Östergötland, SE 581 85 Linköping, Sweden Department of Pharmacology and Clinical Neuroscience, Umeå University, SE 901 87 Umeå, Sweden Occupational and Environmental Medicine, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, SE 581 85 Linköping, Sweden Centre of Occupational and Environmental Medicine, County Council of Östergötland, SE 581 85 Linköping, Sweden.
authors.forename: Nazdar
authors.initials: N
authors.lastname: Ghafouri
authors.forename: Bijar
authors.initials: B
authors.lastname: Ghafouri
authors.forename: Britt
authors.initials: B
authors.lastname: Larsson
authors.forename: Niclas
authors.initials: N
authors.lastname: Stensson
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Fowler
authors.forename: Björn
authors.initials: B
authors.lastname: Gerdle
mesh_terms: D000328:Adult; D000368:Aged; D000577:Amides; D059350:Chronic Pain / Q000473:pathology*; D063388:Endocannabinoids / Q000378:metabolism*; D004983:Ethanolamines / Q000378:metabolism*; D015444:Exercise; D005260:Female; D006801:Humans; D017551:Microdialysis; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism*; D019547:Neck Pain / Q000473:pathology*; D010147:Pain Measurement; D017288:Pain Threshold / Q000502:physiology; D010169:Palmitic Acids / Q000378:metabolism*; D011312:Pressure; D012044:Regression Analysis; D012462:Saline Solution, Hypertonic / Q000009:adverse effects; D020069:Shoulder Pain / Q000473:pathology*; D013229:Stearic Acids / Q000378:metabolism*; D011795:Surveys and Questionnaires; D013997:Time Factors; D055815:Young Adult
chemical_list: D000577:Amides; D063388:Endocannabinoids; D004983:Ethanolamines; D010169:Palmitic Acids; D012462:Saline Solution, Hypertonic; D013229:Stearic Acids; C466089:stearoylethanolamide; C005958:palmidrol
keywords: Cannabinoid; Microdialysis; Myalgia; N-Acylethanolamines; Pain; Palmitoylethanolamide; Widespread pain