Regulation of vascular tone homeostasis by NO and H₂S: Implications in hypertension

Nitric oxide (NO) and hydrogen sulfide (H₂S) are two gasotransmitters that are produced in the vasculature and contribute to the regulation of vascular tone. NO and H₂S are synthesized in both vascular smooth muscle and endothelial cells; NO functions primarily through the sGC/cGMP pathway, and H₂S mainly through activation of the ATP-dependent potassium channels; both leading to relaxation of vascular smooth muscle cells. A deficit in the NO/H₂S homeostasis is involved in the pathogenesis of various cardiovascular diseases, especially hypertension. It is now becoming increasingly clear that there are important interactions between NO and H₂S and that have a profound impact on vascular tone and this may provide insights into the new therapeutic interventions. The aim of this review is to provide a better understanding of individual and interactive roles of NO and H₂S in vascular biology. Overall, available data indicate that both NO and H₂S contribute to vascular (patho)physiology and in regulating blood pressure. In addition, boosting NO and H₂S using various dietary sources or donors could be a hopeful therapeutic strategy in the management of hypertension.