title: In vitro effects of lidocaine on the contractility of equine jejunal smooth muscle challenged by ischaemia-reperfusion injury.
abstract: BACKGROUND
  Post operative ileus (POI) in horses is a severe complication after colic surgery. A commonly used prokinetic drug is lidocaine, which has been shown to have stimulatory effects on intestinal motility. The cellular mechanisms through which lidocaine affects smooth muscle activity are not yet known.
  
  
  OBJECTIVE
  To examine the effects of lidocaine on smooth muscle in vitro and identify mechanisms by which it may affect the contractility of intestinal smooth muscle.
  
  
  OBJECTIVE
  Ischaemia and reperfusion associated with intestinal strangulation can cause smooth muscle injury. Consequently, muscle cell functionality and contractile performance is decreased. Lidocaine can improve basic cell functions and thereby muscle cell contractility especially in ischaemia-reperfusion-challenged smooth muscle.
  
  
  METHODS
  To examine the effects of lidocaine on smooth muscle function directly, isometric force performance was measured in vitro in noninjured and in vivo ischaemia-reperfusion injured smooth muscle tissues. Dose-dependent response of lidocaine was measured in both samples. To assess membrane permeability as a marker of basic cell function, release of creatine kinase (CK) was measured by in vitro incubations.
  
  
  RESULTS
  Lidocaine-stimulated contractility of ischaemia-reperfusion injured smooth muscle was more pronounced than that of noninjured smooth muscle. A 3-phasic dose-dependency was observed with an initial recovery of contractility especially in ischaemia-reperfusion injured smooth muscle followed by a plateau phase where contractility was maintained over a broad concentration range. CK release was decreased by lidocaine.
  
  
  CONCLUSIONS
  Lidocaine may improve smooth muscle contractility and basic cell function by cellular repair mechanisms which are still unknown. Improving contractility of smooth muscle after ischaemia-reperfusion injury is essential in recovery of propulsive intestinal motility.
  
  
  CONCLUSIONS
  Characterisation of the cellular mechanisms of effects of lidocaine, especially on ischaemia-reperfusion injured smooth muscle, may lead to improved treatment strategies for horses with POI.
authors.affiliation: Department of Physiology, University of Veterinary Medicine, Hannover, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Guschlbauer
authors.forename: S
authors.initials: S
authors.lastname: Hoppe
authors.forename: F
authors.initials: F
authors.lastname: Geburek
authors.forename: K
authors.initials: K
authors.lastname: Feige
authors.forename: K
authors.initials: K
authors.lastname: Huber
mesh_terms: D000818:Animals; D003402:Creatine Kinase / Q000378:metabolism; D005260:Female; D006736:Horses; D007583:Jejunum / Q000473:pathology*; D008012:Lidocaine / Q000494:pharmacology*; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects* / Q000502:physiology; D009130:Muscle, Smooth / Q000098:blood supply* / Q000473:pathology; D015427:Reperfusion Injury / Q000473:pathology / Q000662:veterinary*
chemical_list: D008012:Lidocaine; D003402:Creatine Kinase