title: Altered sympathovagal balance and pain hypersensitivity in TNBS-induced colitis.
abstract: BACKGROUND
  Pain hypersensitivity, abnormal motility and autonomic dysfunction contribute to functional symptoms of inflammatory bowel disease (IBD).
  
  
  METHODS
  The aim of this study was to assess: nociceptive thresholds for mechanical allodynia (MA) and thermal hyperalgesia (TH), intestinal motility (distal colonic transit and emptying), and cardiac autonomic neuropathy (indices of heart rate variability - HRV) in male Wistar rats with experimental trinitrobenzene sulfonic acid (TNBS) induced colitis. To identify a potential vagal contribution the bilateral subdiaphragmatic vagotomy (SDV) was performed.
  
  
  RESULTS
  Experimental colitis resulted in a significant decrease in pain threshold (MA 23.60 ±2.12,p< 0.001, TH 8.51 ±1.49,p< 0.001), reduced expulsion time (6.2 ±3.5,p< 0,01) and increase in the sympathetic autonomic activity (LFnu 32.54 ±21.16,p< 0.03). The animals with diminished vagal integrity presented with reduced gastrointestinal motility (39.8 ±25.1,p< 0.01) and a decrease in the parasympathetic high-frequency domain of HRV (HFnu 55.37 ±22.80,p< 0.002). The vagotomized rats with colitis showed the strongest nociceptive response (MA 22.46 ±3.02,p< 0.004; TH 7.99 ±1.12,p< 0.003) as well as significant changes in sympatho-vagal balance on HRV testing (LFnu 28.25 ±14.66,p< 0.04; HFnu 71.34 ±14.55,p< 0.04).
  
  
  CONCLUSIONS
  The relationship between the cardiovascular and gastrointestinal system is modulated by neural, hormonal and inflammatory factors. This leads to dysregulation of the brain-gut interactions in the course of IBD. Sensitization and visceral-somatic convergence trigger pain hypersensitivity and autonomic sympathovagal imbalance. While integral vagal innervation impacts analgesic mechanisms via modulation of the immune response, SDV raises sympathetic activity and induces excessive hyperalgesia.
authors.affiliation: Department of Pathophysiology, Jagiellonian University Medical College, Krakow, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Ciesielczyk
authors.affiliation: Department of Pathophysiology, Jagiellonian University Medical College, Krakow, Poland.
authors.forename: Agata
authors.initials: A
authors.lastname: Furgała
authors.affiliation: Department of Pathophysiology, Jagiellonian University Medical College, Krakow, Poland.
authors.forename: Łukasz
authors.initials: Ł
authors.lastname: Dobrek
authors.affiliation: Department of Pathophysiology, Jagiellonian University Medical College, Krakow, Poland.
authors.forename: Kajetan
authors.initials: K
authors.lastname: Juszczak
authors.affiliation: Department of Pathophysiology, Jagiellonian University Medical College, Krakow, Poland.
authors.forename: Piotr
authors.initials: P
authors.lastname: Thor
keywords: colitis; heart rate variability; inflammatory bowel disease; pain hypersensitivity