Mechanisms of actions of hydrogen sulphide on rat distal colonic epithelium

Abstract

BACKGROUND AND PURPOSEThe aim of this study was to clarify the mechanisms by which hydrogen sulphide (H2S) affects ion secretion across rat distal colonic epithelium. EXPERIMENTAL APPROACHChanges in short-circuit current induced by the H2S-donor, sodium hydrosulphide (NaHS; 10 mmol·L KEY RESULTSNaHS had a biphasic effect on overall currents across the basolateral membrane: an initial inhibition followed by a secondary stimulation. Both a scilliroside-sensitive action on the Na CONCLUSIONS AND IMPLICATIONSATP-sensitive and Ca 2+-dependent basolateral K + conductances, the basolateral Na + -K + -pump as well as Ca 2+ transporters were involved in the action of H2S in regulating colonic ion secretion. [Ca 2+ Abbreviations

Regulation of Colonic Ion Transport by Gasotransmitters

“…This response is dependent on the presence of extracellular Na ϩ and is blocked by 2Ј,4Ј-dichlorobenzamil, an inhibitor of the Na quenching experiments. 32) In contrast, the secondary rise of the cytosolic Ca 2ϩ concentration was independent from the presence of extracellular Ca 2ϩ . 31) The pathway, by which this influx occurs, is not known.…”

“…ATP-sensitive K ϩ channels, which are inhibited by glibenclamide, and Ca 2ϩ -dependent K ϩ channels, which are sensitive to quarternary amines such as tetrapentylammonium. 32) This forces anion secretion by enhancing the driving force for Cl Ϫ efflux across the apical membrane. The action of H 2 S on basolateral K ϩ channels is supported by a biphasic change in the 3Na…”

H2S and its role in redox signaling

“…H 2 S is proposed to play a regulatory role in the gastrointestinal tract by modulating intestinal contractility [193], by affecting colonic ion secretion via involvement of potassium channels [194,195] and by its excitatory action on enteric neuorons [196–198]. Intestinal microflora produces large amounts of H 2 S by degradation of sulfur-containing organic compounds and by dissimilatory sulfate reduction.…”

Hydrogen sulfide decreases β-adrenergic agonist-stimulated lung liquid clearance by inhibiting ENaC-mediated transepithelial sodium absorption

“…Furthermore, Diener and colleagues (67) demonstrated a secretory response to H 2 S in rat colon epithelia. In this tissue, H 2 S induces a secretion of chloride (37,66), which would trigger transepithelial liquid secretion.…”