title: Role of hydrogen sulfide as a gasotransmitter in modulating contractile activity of circular muscle of rat jejunum.
abstract: OBJECTIVE
  Our aim was to determine mechanisms of action of the gasotransmitter hydrogen sulfide (H(2)S) on contractile activity in circular muscle of rat jejunum.
  
  
  METHODS
  Jejunal circular muscle strips were prepared to measure isometric contractions. Effects of sodium hydrosulfide (NaHS), a H(2)S donor, were evaluated on spontaneous contractile activity and after pre-contraction with bethanechol. L-cysteine was evaluated as an endogenous H(2)S donor. We evaluated extrinsic nerves, enteric nervous system, visceral afferent nerves, nitric oxide, K(ATP)+ and K(Ca)+ channels, and myosin light chain phosphatase on action of H(2)S using non-adrenergic/non-cholinergic conditions, tetrodotoxin, capsaicin, L-N(G)-nitro arginine (L-NNA), glibenclamide, apamin, and calyculin A, respectively, and electrical field stimulation (EFS).
  
  
  RESULTS
  NaHS dose-dependently and reversibly inhibited spontaneous and bethanechol-stimulated contractile activity (p < 0.05). L-cysteine had a dose-dependent inhibitory effect. Non-adrenergic/non-cholinergic conditions, tetrodotoxin, capsaicin, L-NNA, or apamin had no effect on contractile inhibition by NaHS; in contrast, low-dose glibenclamide and calyculin A prevented NaHS-induced inhibition. We could not demonstrate H(2)S release by EFS.
  
  
  CONCLUSIONS
  H(2)S inhibits contractile activity of jejunal circular muscle dose-dependently, in part by K(ATP)+ channels and via myosin light chain phosphatase, but not via pathways mediated by the extrinsic or enteric nervous system, visceral afferent nerves, nitric oxide, or K(Ca)+ channels.
authors: Gastroenterology Research Unit and Division of Gastroenterologic and General Surgery, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
authors: Munenori
authors: M
authors: Nagao
authors: Judith A
authors: JA
authors: Duenes
authors: Michael G
authors: MG
authors: Sarr
mesh_terms: D000818:Animals; D018723:Bethanechol / Q000008:administration & dosage / Q000494:pharmacology; D003545:Cysteine / Q000008:administration & dosage / Q000494:pharmacology / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D005769:Gastrointestinal Motility / Q000187:drug effects / Q000502:physiology*; D006862:Hydrogen Sulfide / Q000378:metabolism / Q000494:pharmacology*; D007583:Jejunum / Q000187:drug effects / Q000502:physiology*; D008297:Male; D018721:Muscarinic Agonists / Q000008:administration & dosage / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology*; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D013440:Sulfides / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D018721:Muscarinic Agonists; D013440:Sulfides; D018723:Bethanechol; C025451:sodium bisulfide; D003545:Cysteine; D006862:Hydrogen Sulfide