The effect of the long-term inhibition of hydrogen sulfide production on the reactivity of the cardiovascular system in Wistar rats.

In this study, we investigated the blood pressure responses of the peripheral bed in vivo after chronic hydrogen sulfide (HS) inhibition combined with acute nitric oxide (NO) deficiency. We also evaluated the role of endogenously produced HS in the vasoactive responses of large- and medium-sized arteries in vitro. Changes in integrated blood pressure responses were measured after chronic inhibition of cystathionine-γ-lyase, an enzyme involved in HS synthesis, with DL-propargylglycine (PPG), and acute inhibition of NO-synthase with nonspecific L-N-nitro arginine methyl ester (L-NAME), and vasoactive responses of the thoracic aorta (TA) and mesenteric artery (MA) were investigated after acute incubation with PPG. We confirmed that chronic HS deficiency had no effect on blood pressure, heart trophycity, noradrenaline, and HS donor vasoactive responses but induced renal hypertrophy and a decrease in acetylcholine-induced hypotensive and L-NAME-induced hypertensive responses. Acute HS deficiency led to an increase in basal tone (MA) or active tone (TA), whereas endothelium-dependent vasorelaxation remained unaffected. Long-term administration of PPG revealed a role of endogenous HS in the bioavailability of endothelial NO in peripheral arteries. When both HS and NO were lacking, the activation of HS-independent compensatory mechanisms plays an important role in maintaining the vasodilator responses of the cardiovascular system.