Hydrogen sulfide inhibits activity of three isoforms of recombinant nitric oxide synthase.

To clarify the presence of cross-talk between H(2)S and NO, we investigated effect of NaHS, an H(2)S donor, on activity of recombinant NO synthase (NOS) isoforms. Activity of all nNOS, iNOS and eNOS was inhibited by NaHS (IC(50): 0.13-0.

Hydrogen sulfide causes relaxation in mouse bronchial smooth muscle.

We investigated the effects of NaHS, a hydrogen sulfide (H(2)S) donor, on the tension of isolated mouse and guinea-pig bronchial rings. NaHS at 0.01 - 10 mM had no effect on the tone of those preparations without precontraction.

Distinct activity of peptide mimetic intracellular ligands (pepducins) for proteinase-activated receptor-1 in multiple cells/tissues.

Proteinase-activated receptor-1 (PAR1), a G protein-coupled receptor (GPCR) for thrombin, can be activated not only by PAR1-activating peptides (PAR1APs) based on the N-terminal cryptic tethered ligand sequence but also by an N-palmitoylated (Pal) peptide, Pal-RCLSSSAVANRSKKSRALF-amide (P1pal-19), based on the intracellular loop 3 of PAR1, designated pepducin, in human platelets or PAR1-transfected cells. The present article evaluated the actions of P1pal-19 and also the shorter peptide, Pal-RCLSSSAVANRS-amide (P1pal-12), known as a possible PAR1 antagonist, in multiple cells/tissues that naturally express PAR1. P1pal-19 as well as a PAR1AP, TFLLR-amide, evoked cytosolic Ca(2+) mobilization in cultured human lung epithelial cells (A549) and rat gastric mucosal epithelial cells (RGM1).

Direct inhibition of endothelial nitric oxide synthase by hydrogen sulfide: contribution to dual modulation of vascular tension.

We characterized actions of hydrogen sulfide (H(2)S) on tension of isolated rat and mouse aortae, and then examined if H(2)S could directly modulate activity of endothelial nitric oxide (NO) synthase (eNOS). Isometric tension was recorded in rat and mouse aortic rings. Activity of recombinant bovine eNOS was determined as conversion of [(3)H]-arginine into [(3)H]-citrulline.