1. Hydrogen sulfide as an oxygen sensor/transducer in vertebrate hypoxic vasoconstriction and hypoxic vasodilation.
- Author
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Olson, Kenneth R., Dombkowski, Ryan A., Russell, Michael J., Doellman, Meredith M., Head, Sally K., Whitfield, Nathan L., and Madden, Jane A.
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VASCULAR smooth muscle ,HYDROGEN sulfide ,METABOLISM ,OXIDATION-reduction reaction ,BLOOD vessels - Abstract
How vertebrate blood vessels sense acute hypoxia and respond either by constricting (hypoxic vasoconstriction) or dilating (hypoxic vasodilation) has not been resolved. In the present study we compared the mechanical and electrical responses of select blood vessels to hypoxia and H
2 S, measured vascular H2 S production, and evaluated the effects of inhibitors of H2 S synthesis and addition of the H2 S precursor, cysteine, on hypoxic vasoconstriction and hypoxic vasodilation. We found that: (1) in all vertebrate vessels examined to date, hypoxia and H2 S produce temporally and quantitatively identical responses even though the responses vary from constriction (lamprey dorsal aorta; IDA), to dilation (rat aorta; rA), to multi-phasic (rat and bovine pulmonary arteries; rPA and bPA, respectively). (2) The responses of IDA, rA and bPA to hypoxia and H2 S appear competitive; in the presence of one stimulus, the response to the other stimulus is substantially or completely eliminated. (3) Hypoxia and H2 S produce the same degree of cell depolarization in bPA. (4) H2 S is constitutively synthesized by IDA and bPA vascular smooth muscle. (5) Inhibition of H2 S synthesis inhibits the hypoxic response of IDA, rA, rPA and bPA. (6) Addition of the H2 S precursor, cysteine, doubles hypoxic contraction in IDA, prolongs contraction in bPA and alters the re-oxygenation response of rA. These studies suggest that H2 S may serve as an O2 sensor/transducer in the vascular responses to hypoxia. In this model, the concentration of vasoactive H2 S in the vessel is governed by the balance between endogenous H2 S production and its oxidation by available O2 . [ABSTRACT FROM AUTHOR]- Published
- 2006
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