title: Effects of hydrogen sulphide on motility patterns in the rat colon.
abstract: OBJECTIVE
  Hydrogen sulphide (H2 S) is an endogenous gaseous signalling molecule with putative functions in gastrointestinal motility regulation. Characterization of H2 S effects on colonic motility is crucial to establish its potential use as therapeutic agent in the treatment of colonic disorders.
  
  
  METHODS
  H2 S effects on colonic motility were characterized using video recordings and construction of spatio-temporal maps. Microelectrode and muscle bath studies were performed to investigate the mechanisms underlying H2 S effects. NaHS was used as the source of H2 S.
  
  
  RESULTS
  Rhythmic propulsive motor complexes (RPMCs) and ripples were observed in colonic spatio-temporal maps. Serosal addition of NaHS concentration-dependently inhibited RPMCs. In contrast, NaHS increased amplitude of the ripples without changing their frequency. Therefore, ripples became the predominant motor pattern. Neuronal blockade with lidocaine inhibited RPMCs, which were restored after administration of carbachol. Subsequent addition of NaHS inhibited RPMCs. Luminal addition of NaHS did not modify motility patterns. NaHS inhibited cholinergic excitatory junction potentials, carbachol-induced contractions and hyperpolarized smooth muscle cells, but did not modify slow wave activity.
  
  
  CONCLUSIONS
  H2 S modulated colonic motility inhibiting propulsive contractile activity and enhancing the amplitude of ripples, promoting mixing. Muscle hyperpolarization and inhibition of neurally mediated cholinergic responses contributed to the inhibitory effect on propulsive activity. H2 S effects were not related to changes in the frequency of slow wave activity originating in the network of interstitial cells of Cajal located near the submuscular plexus. Luminal H2 S did not modify colonic motility probably because of epithelial detoxification.
authors.affiliation: Department of Cell Biology, Physiology and Immunology/Neuroscience Institute, Universitat Autònoma de Barcelona (UAB), Barcelona, Spain.
authors.forename: V
authors.initials: V
authors.lastname: Gil
authors.forename: Sp
authors.initials: S
authors.lastname: Parsons
authors.forename: D
authors.initials: D
authors.lastname: Gallego
authors.forename: Jd
authors.initials: J
authors.lastname: Huizinga
authors.forename: M
authors.initials: M
authors.lastname: Jimenez
mesh_terms: D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D003106:Colon / Q000187:drug effects / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005769:Gastrointestinal Motility / Q000187:drug effects*; D006862:Hydrogen Sulfide / Q000494:pharmacology*; D056885:Interstitial Cells of Cajal / Q000187:drug effects / Q000378:metabolism; D008012:Lidocaine / Q000494:pharmacology; D008297:Male; D008839:Microelectrodes; D009119:Muscle Contraction / Q000187:drug effects*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D062211:Spatio-Temporal Analysis; D013440:Sulfides / Q000008:administration & dosage*; D014741:Video Recording
chemical_list: D013440:Sulfides; D002217:Carbachol; D008012:Lidocaine; C025451:sodium bisulfide; D006862:Hydrogen Sulfide