Epithelial Electrolyte Transport Physiology and the Gasotransmitter Hydrogen Sulfide

Figure 3

Exogenous hydrogen sulfide stimulates electrolyte secretion in human colon via activation of submucosal neurons. H₂S stimulates TRPV1 channels in extrinsic primary afferent fibres, which leads to the release of substance P (SP). SP binds to neurokinin receptors (NK) 1 and 2 of enteric cholinergic secretomotor neurons in submucosal ganglia. The subsequently released acetyl choline (ACh) binds to muscarinergic acetyl choline receptors (mAChR) in the epithelial cells. This stimulates a rise in intracellular calcium concentrations which triggers electrolyte secretion by activating calcium-dependent chloride (CaCC) and potassium () channels.