title: Quantifying the effects of inactin vs Isoflurane anesthesia on gastrointestinal motility in rats using dynamic magnetic resonance imaging and spatio-temporal maps.
abstract: BACKGROUND
  Anesthetics are commonly applied in animal studies of gastrointestinal (GI) function. Different anesthetics alter smooth-muscle motility in different ways. The aim of this study is to quantify and compare non-invasively with magnetic resonance imaging (MRI) the motility patterns of the rat gut when anesthetized with inactin vs isoflurane anesthetics in the fed state.
  
  
  METHODS
  Rats were given an oral gavage of MRI contrast agent for improved visualization of the GI tract. Two-dimensional images through the jejunum of the pre- and postanesthetized rat in the fed state were acquired every 168 ms. Image registration, segmentation, and postprocessing algorithms were applied to produce spatio-temporal maps that were used to quantify peristaltic and segmental motions in the jejunum region interspersed between periods of inactivity.
  
  
  RESULTS
  There were significantly longer periods of inactivity in the rats treated with isoflurane than in those treated with inactin (179.9 ± 22.4 s vs 17.7 ± 10.3 s). The speed of propagation and wavelength of peristalsis, and the frequency and speed of pattern switching of segmental motility, were higher (p < 0.05) in rats treated with inactin.
  
  
  CONCLUSIONS
  Isoflurane and inactin anesthetics produce significantly different motility behavior with the rat's GI tract in the fed state. Isoflurane anesthetic, results in a reduced frequency of occurrence of motility periods and an overall reduced level of motility in comparison with inactin.
authors.affiliation: Department of Bioengineering, Pennsylvania State University, University Park, PA, USA.
authors.forename: A C
authors.initials: AC
authors.lastname: Ailiani
authors.forename: T
authors.initials: T
authors.lastname: Neuberger
authors.forename: J G
authors.initials: JG
authors.lastname: Brasseur
authors.forename: G
authors.initials: G
authors.lastname: Banco
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.forename: N B
authors.initials: NB
authors.lastname: Smith
authors.forename: A G
authors.initials: AG
authors.lastname: Webb
mesh_terms: D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D005769:Gastrointestinal Motility / Q000187:drug effects*; D007530:Isoflurane / Q000494:pharmacology*; D008279:Magnetic Resonance Imaging; D051381:Rats; D013874:Thiopental / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D018685:Anesthetics, Inhalation; C004316:thiobutabarbital; D007530:Isoflurane; D013874:Thiopental
keywords: MRI; anesthesia; dynamic MRI; inactin; intestine; isoflurane; motility; peristalsis; segmentation