Hydrogen sulfide elicits vasodilation in the human cutaneous circulation in a dose‐dependent manner (1104.7)

Hydrogen sulfide (H 2 S) is a gasotransmitter that is a putative endothelial‐derived hyperpolarizing factor that causes vasodilation (VD) through K ATP channels. However, little is known about the vascular effects of H 2 S in humans; thus we used an exogenous H 2 S donor to characterize in vivo H 2 S‐mediated VD in the skin of healthy adults. Microdialysis fibers were placed in the forearm skin of 5 men and women (23‐56 yrs old) for local delivery of (1) a H 2 S donor (Na 2 S) and (2) Na s S + glybenclamide (1mM; a K ATP channel inhibitor). Skin blood flow was measured by laser‐Doppler flowmetry and recorded as cutaneous vascular conductance (CVC = laser‐Doppler flux/ mean arterial pressure) during a Na 2 S dose‐response protocol. All data were normalized as % maximal CVC (local heating and infusion of 28 mM SNP). The table displays mean ± SE for each site at each dose. Na 2 S elicited VD in a dose ‐dependent manner in all subjects with no significant difference between sites at each dose. Beyond 60mM Na 2 S, minimal increases in VD were observed. These data suggest that a H 2 S donor effectively elicits VD in vivo in healthy human skin. Further, hydrogen sulfide appears to elicit VD via mechanism other than those dependent on K ATP channels.