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Oxygen Dependency of Hydrogen Sulfide‐mediated Vasoconstriction in Cyclostome Aortas
Author(s) -
Olson Kenneth R.,
Forgan Leonard G.,
Dombkowski Ryan A.,
Forster Malcolm E.
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.1174.5
Subject(s) - vasoconstriction , chemistry , endocrinology , medicine , vascular smooth muscle , hypoxia (environmental) , oxygen , anatomy , biochemistry , biology , organic chemistry , smooth muscle
Hydrogen sulfide (H 2 S) is a vasoregulatory molecule and recent evidence suggests it may be an O 2 sensor for hypoxic vasoconstriction (HVC). Here we examined H 2 S ‐ O 2 interactions in hagfish vessels. In myographic studies, H 2 S (Na 2 S) dose‐dependently constricted dorsal aortas (DA) and efferent branchial arteries (EBA) but did affect ventral aorta or afferent branchial arteries; hypoxia produces similar responses. Hypoxia enhanced DA sensitivity to H 2 S. HVC in DA was augmented by the H 2 S precursor cysteine and inhibited by aminooxy acetate (AOA), an inhibitor of the H 2 S‐synthesizing enzyme, CBS. HVC was unaffected by propargyl glycine, the CSE inhibitor. DA O 2 consumption (MO 2 ) was constant between PO 2 15–115 mmHg, but decreased when PO 2 <15 mmHg and increased after PO 2 exceeded 115 mmHg. 10 uM H 2 S increased MO 2 , whereas MO 2 fell when [H 2 S] >100 uM. Consistent with the effects on HVC, cysteine increased and AOA decreased MO 2 . These results show that H 2 S is a monophasic vasoconstrictor of specific cyclostome vessels and because hagfish lack vascular NO, and vascular sensitivity was enhanced at low PO 2 , it is unlikely that H 2 S contractions are mediated by either H 2 S‐NO interaction or an oxidation product of H 2 S. They also support the hypothesis that H 2 S metabolism is an O 2 sensor in vertebrate vascular smooth muscle. Support: NSF IBN 0235223, IOS 0641436 and Erskin Fellowship (KRO)