Relaxing Effect of Hydrogen Sulfide on Isolated Bovine Mesenteric Lymph Nodes

We studied the effects and mechanisms of action of NaHS, an H₂S donor, on isolated phenylephrine-precontracted bovine mesenteric lymph nodes. NaHS induced concentration-dependent relaxation of lymph nodes. Removal of the endothelium reduced, but did not abolish the relaxing effect of NaHS. The relaxing effect was reduced by NO synthase inhibitor L-NAME, soluble guanylate cyclase inhibitor ODQ, ATP-sensitive K⁺ channel blocker glibenclamide, and a combination charybdotoxin+apamin (blockers of small- and intermediate-conductance Ca²⁺-activated K⁺ channels). Thus, the relaxing effect of H₂S on lymph nodes is mediated by several parallel mechanisms. H₂S induces relaxation of LN and modulates the rate of lymph transport, thereby affecting the development of immune processes in the body.