title: Contractile function of the mechanically lengthened intestine.
abstract: BACKGROUND
  The application of longitudinal mechanical force induces lengthening of the small intestine. The purpose of this study is to evaluate the contractile function of the mechanically lengthened jejunum in a rodent model.
  
  
  METHODS
  Three groups of rats including normal jejunum, isolated jejunal segment without mechanical lengthening, and isolated lengthened jejunal segment, were studied for contractile function. The isometric contractions of jejunal segments were investigated in organ baths for spontaneous activity and response to potassium chloride and cholinergic carbachol.
  
  
  RESULTS
  The normal control group showed a basal spontaneous activity with an average frequency of 33 +/- 0.68 contractions per min (cpm). The basal spontaneous activity for the isolated group had an average frequency of 26 +/- 2.7 cpm and for the lengthened group had an average frequency of 24 +/- 5.7 cpm. Although the normal control group had a higher frequency of basal spontaneous activity as compared to either the isolated or lengthened groups, there was no statistically significant difference between the frequencies in the isolated and the lengthened groups. All three groups demonstrated a sustained increase in tension upon administration of either potassium chloride or carbachol.
  
  
  CONCLUSIONS
  The response to pharmacological stimulation, as measured by total area under the tension curve and maximal change in basal tone, was larger in the normal group than in the isolated groups. The addition of longitudinal mechanical force to lengthen the isolated jejunal segment did not further alter this change.
authors.affiliation: Division of Pediatric Surgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA.
authors.forename: Julianne
authors.initials: J
authors.lastname: Mendoza
authors.forename: Chia-yu
authors.initials: CY
authors.lastname: Chang
authors.forename: Carrie L
authors.initials: CL
authors.lastname: Blalock
authors.forename: James B
authors.initials: JB
authors.lastname: Atkinson
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Wu
authors.forename: James C Y
authors.initials: JC
authors.lastname: Dunn
mesh_terms: D000818:Animals; D019540:Area Under Curve; D002217:Carbachol / Q000494:pharmacology; D018679:Cholinergic Agonists / Q000494:pharmacology; D005260:Female; D007537:Isometric Contraction / Q000187:drug effects / Q000502:physiology*; D007583:Jejunum / Q000033:anatomy & histology / Q000502:physiology*; D009130:Muscle, Smooth / Q000502:physiology*; D009929:Organ Size; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013314:Stress, Mechanical
chemical_list: D018679:Cholinergic Agonists; D011189:Potassium Chloride; D002217:Carbachol