title: Interstitial concentration of serotonin is increased in myalgic human trapezius muscle during rest, repetitive work and mental stress - an in vivo microdialysis study.
abstract: OBJECTIVE
  The pathophysiology of trapezius myalgia is not fully elucidated. Serotonin (5-HT) is involved in modulation of nociception and hyperalgesia. Our aim was to compare the interstitial 5-HT levels of the trapezius muscle in women with chronic trapezius myalgia and in pain-free controls.
  
  
  METHODS
  Microdialysate of the trapezius muscle collected every 20 minutes during rest, work (100 min) and stress (20 min) was used to study the dynamics of 5-HT in women with chronic trapezius myalgia (MYA; n=18) and in pain-free controls (CON; n=30).
  
  
  RESULTS
  MYA had higher levels of 5-HT than CON at baseline, during repetitive work, during mental stress and during recovery. There were no significant time effects on 5-HT levels.
  
  
  CONCLUSIONS
  5-HT has the potential of a biomarker of chronic myalgia. Elevated levels of 5-HT may be involved in maintenance of habitual chronic pain and might contribute to increased pain during exercise by facilitating the effect of released algesic substances linked to such muscle demands.
authors: Rehabilitation Medicine, Department of Clinical and Experimental Medicine, Linköping University and Pain and Rehabilitation Centre, University Hospital, Linköping, Sweden.
authors: Bijar
authors: B
authors: Ghafouri
authors: Britt K
authors: BK
authors: Larsson
authors: Anna
authors: A
authors: Sjörs
authors: Per
authors: P
authors: Leandersson
authors: Björn U C
authors: BU
authors: Gerdle
mesh_terms: D000328:Adult; D045604:Extracellular Fluid / Q000378:metabolism; D005260:Female; D006801:Humans; D017551:Microdialysis; D008875:Middle Aged; D008954:Models, Biological; D009132:Muscles / Q000378:metabolism*; D009135:Muscular Diseases / Q000150:complications / Q000378:metabolism*; D010147:Pain Measurement; D012146:Rest / Q000502:physiology*; D012701:Serotonin / Q000378:metabolism*; D013315:Stress, Psychological / Q000150:complications / Q000378:metabolism*; D014937:Work / Q000502:physiology*
chemical_list: D012701:Serotonin