Role of nitric oxide and calcium ions in the effects of hydrogen sulfide on contractile activity of rat jejunum

Abstract

This study was performed to explore the role of nitric oxide, intracellular and extracellular calcium in the effects of hydrogen sulfide on spontaneous and carbachol-induced contractions of a rat jejunum preparation during a isometric contraction. Application of H2S donor, sodium hydrosulfide, led to a decrease in tonic tension, the amplitude and frequency of spontaneous contractions, as well as in the amplitude induced by carbachol, a nonspecific acetylcholine receptor agonist. Inhibiting the production of endogenous NO synthesis by with L-NAME, the effect of H2S donor remained unchanged, while in the presence of SNAP, a NO donor, the effects of NaHS on the amplitude of spontaneous and carbachol-induced contractions were less pronounced. Dantrolene, a ryanodine receptor inhibitor was used to stop a decrease in tonic tension in the presence of NaHS. The calcium-free solution reduced the inhibitory effect of NaHS on carbachol-induced contractions. This suggests that the inhibitory effect of H2S is associated with the dynamics of the intracellular concentration of calcium ions, and the interaction between NO and H2S occurs at the level of common targets of two gases.