Hydrogen sulfide as a neuromodulator of the vascular tone.

Hydrogen sulfide (H ₂ S) is a unique signaling molecule that, along with carbon monoxide and nitric oxide, belongs to the gasotransmitters family. H ₂ S is endogenously synthesized by enzymatic and non-enzymatic pathways. Three enzymatic pathways involving cystathionine-γ-lyase, cystathionine-β-synthetase, and 3-mercaptopyruvate sulfurtransferase are known as endogenous sources of H ₂ S. This gaseous molecule has recently emerged as a regulator of many systems and physiological functions, including the cardiovascular system where it controls the vascular tone of small arteries. In this context, H ₂ S leads to vasorelaxation by regulating the activity of vascular smooth muscle cells, endothelial cells, and perivascular nerves. Specifically, H ₂ S modulates the functionality of different ion channels to inhibit the autonomic sympathetic outflow-by either central or peripheral mechanisms-or to stimulate perivascular sensory nerves. These mechanisms are particularly relevant for those pathological conditions associated with impaired neuromodulation of vascular tone. In this regard, exogenous H ₂ S administration efficiently attenuates the increased activity of the sympathetic nervous system often seen in patients with certain pathologies. These effects of H ₂ S on the autonomic sympathetic outflow will be the primary focus of this review. Thereafter, we will discuss the central and peripheral regulatory effects of H ₂ S on vascular tone. Finally, we will provide the audience with a detailed summary of the current pathological implications of H ₂ S modulation on the neural regulation of vascular tone.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. We confirm that the manuscript has been read and approved by all named authors and that there are no other persons who satisfied the criteria for authorship but are not listed. We further confirm that the order of authors listed in the manuscript has been approved by all of us.
(Copyright © 2022 Elsevier B.V. All rights reserved.)