Characterization of H2S as a vasodilator in human cutaneous vasculature

Open Access
Author:
Davin, Marikah I
Area of Honors:
Kinesiology
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Lacy A Holowatz, Thesis Supervisor
  • Stephen Jacob Piazza, Honors Advisor
  • William Lawrence Kenney Jr., Faculty Reader
Keywords:
  • hydrogen sulfide
  • skin blood flow
  • vasodilation
Abstract:
Hydrogen sulfide (H2S) is thought to be the third gaseous mediator, nitric oxide and carbon monoxide being the other two. It is hypothesized that H2S is one of the endothelium-derived hyperpolarization factors (EDHF), promoting vasodilation. In vascular smooth muscle H2S is proposed to contribute to vasodilation through activation of KATP channels. This project systematically characterized the signaling pathway of H2S in the human cutaneous microcirculation. H2S-induced vasodilation was elicited by the exogenous administration of NaHS via microdialysis in a dose-dependent manner (0-100mM). The administration of a KATP inhibitor, glybenclamide (1mM), attenuated H2S-induced dilation confirming that H2S functions through KATP channels. Skin blood flow was measured using laser-Doppler flowmetry, from which cutaneous vascular conductance (CVC) was calculated and data were presented as a percentage of maximum CVC (%CVCMAX). Sulfide activity from the effluent of the microdialysis fibers was measured for each dose by an ion selective electrode and then compared against a standard curve to determine sulfide concentration. A dose response curve was created for NaHS as well as a protocol for administering and measuring H2S to be used in future studies to characterize the contribution of H2S in aged and diseased human skin.