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Hydrogen sulfide as an endogenous regulator of vascular smooth muscle tone in trout
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| Zeitschriftentitel: | American Journal of Physiology-Regulatory, Integrative and Comparative Physiology |
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| Personen und Körperschaften: | , , |
| In: | American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 286, 2004, 4, S. R678-R685 |
| Format: | E-Article |
| Sprache: | Englisch |
| veröffentlicht: |
American Physiological Society
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| Schlagwörter: |
| Zusammenfassung: | <jats:p> Hydrogen sulfide (H<jats:sub>2</jats:sub>S) is an endogenous vasodilator in mammals, but its presence and function in other vertebrates is unknown. We generated H<jats:sub>2</jats:sub>S from NaHS and examined the effects on isolated efferent branchial arteries from steelhead (stEBA) or rainbow (rtEBA) trout. H<jats:sub>2</jats:sub>S concentration was measured colorimetrically (CM) and with ion-selective electrodes (ISE) in rainbow trout plasma. NaHS produced a triphasic response consisting of a relaxation (phase 1), constriction (phase 2), and relaxation (phase 3) in both unstimulated vessels and in stEBA precontracted with carbachol (Carb). Phase 1 and phase 3 in stEBA were decreased and phase 2 increased in unstimulated vessels by K<jats:sup>+</jats:sup><jats:sub>ATP</jats:sub> channel inhibition (glibenclamide), or a cocktail of inhibitors of cyclooxygenase, lipoxygenase, and cytochrome P-450 (indomethacin, esculetin, and clotrimazole). Inhibition of soluble guanylate cyclase with ODQ or NS-2028 inhibited phase 3 in stEBA, although NaHS decreased cGMP production by rtEBA. stEBA phase 2 contractions were partially inhibited by the myosin light chain kinase inhibitor, ML-9, but unaffected by L-type calcium channel inhibition (methoxyverapamil), whereas contraction in rtEBA was partially inhibited by nifedipine or removal of extracellular calcium. Phase 3 relaxations were more pronounced in stEBA precontracted with Carb and norepinephrine (NE) than those contracted by KCl or K<jats:sub>2</jats:sub>SO<jats:sub>4</jats:sub>. stEBA phase 2 and phase 3 responses were dose dependent (EC<jats:sub>50</jats:sub> = 1.1 ± 1.2 × 10<jats:sup>-3</jats:sup> M and 6.7 ± 0.9 × 10<jats:sup>-5</jats:sup> M, respectively; n = 7). NaHS was also vasoactive in steelhead bulbus arteriosus, celiacomesenteric arteries, and anterior cardinal veins. Rainbow trout plasma sulfide concentration was 4.0 ± 0.3 × 10<jats:sup>-5</jats:sup> M, n = 4 (CM) and 3.8 ± 0.4 × 10<jats:sup>-5</jats:sup> M, n = 9 (ISE); similar to phase 3 EC<jats:sub>50</jats:sub>. Because NaHS has substantial vasoactive effects at physiological plasma concentrations, we propose that its soluble derivative, H<jats:sub>2</jats:sub>S, is a tonically active endogenous vasoregulator in trout. </jats:p> |
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| Umfang: | R678-R685 |
| ISSN: |
0363-6119
1522-1490 |
| DOI: | 10.1152/ajpregu.00419.2003 |