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. 1996 Jul;118(5):1147–1152. doi: 10.1111/j.1476-5381.1996.tb15517.x

Effects of cytochrome P450 inhibitors on EDHF-mediated relaxation in the rat hepatic artery.

P M Zygmunt 1, G Edwards 1, A H Weston 1, S C Davis 1, E D Högestätt 1
PMCID: PMC1909609  PMID: 8818337

Abstract

1. The possibility that the endothelium-derived hyperpolarising factor (EDHF) in the rat hepatic artery is a cytochrome P450 mono-oxygenase metabolite of arachidonic acid was examined in the present study. In this preparation, acetylcholine elicits EDHF-mediated relaxations in the presence of the nitric oxide (NO) synthase and cyclo-oxygenase inhibitors N omega-nitro-L-arginine (L-NOARG) and indomethacin, respectively. 2. 17-Octadecynoic acid (17-ODYA, 50 microM), a suicide-substrate inhibitor of the cytochrome P450 mono-oxygenases responsible for the production of 5,6-, 8,9-, 11,12- and 14,15-epoxyeicosatrienoic acids (EETs), had no effect on acetylcholine-induced relaxations in the presence of L-NOARG (0.3 mM) plus indomethacin (10 microM). Furthermore, 5,6-, 8,9-, 11,12- and 14,15- EETs failed to relax arteries without endothelium in the presence of L-NOARG plus indomethacin. 3. Proadifen and clotrimazole, which are inhibitors of several isoforms of cytochrome P450 mono-oxygenases, inhibited acetylcholine-induced relaxations in the presence of L-NOARG plus indomethacin. The concentration of acetylcholine which caused half-maximal relaxation was about 3 and 30 times higher in the presence than in the absence of clotrimazole (3 microM) and proadifen (10 microM), respectively. The maximal relaxation was reduced by proadifen but not by clotrimazole. Proadifen (10 microM) also inhibited acetylcholine-induced hyperpolarization in the presence of L-NOARG plus indomethacin. 4. In the presence of 30 mM K+ plus indomethacin (10 microM), acetylcholine induced an L-NOARG-sensitive relaxation mediated via release of NO. Under these conditions, proadifen (10 microM) shifted the acetylcholine concentration-response curve 6 fold to the right without affecting the maximal relaxation. Clotrimazole (3 microM) was without effect on these responses. The relaxant actions of the NO donor, 3-morpholino-sydnonimine, were unaffected by proadifen (10 microM). 5. The relaxant effects of the opener of ATP-sensitive potassium channels, levcromakalim, were abolished by proadifen (10 microM) and strongly attenuated by clotrimazole (3 microM). Proadifen (10 microM) also abolished the hyperpolarization induced by levcromakalim (1 microM). 6. The lack of effect of 17-ODYA on relaxations mediated by EDHF, together with the failure of extracellularly-applied EETs to produce relaxation, collectively suggest that EDHF is not an EET in the rat hepatic artery. It seems likely that inhibition of ion channels in the smooth muscle rather than reduced EDHF formation in the endothelium offers a better explanation for the actions of the cytochrome P450 inhibitors proadifen and clotrimazole.

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Selected References

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  1. Abraham N. G., Pinto A., Mullane K. M., Levere R. D., Spokas E. Presence of cytochrome P-450-dependent monooxygenase in intimal cells of the hog aorta. Hypertension. 1985 Nov-Dec;7(6 Pt 1):899–904. doi: 10.1161/01.hyp.7.6.899. [DOI] [PubMed] [Google Scholar]
  2. Alvarez J., Montero M., Garcia-Sancho J. High affinity inhibition of Ca(2+)-dependent K+ channels by cytochrome P-450 inhibitors. J Biol Chem. 1992 Jun 15;267(17):11789–11793. [PubMed] [Google Scholar]
  3. Bauersachs J., Hecker M., Busse R. Display of the characteristics of endothelium-derived hyperpolarizing factor by a cytochrome P450-derived arachidonic acid metabolite in the coronary microcirculation. Br J Pharmacol. 1994 Dec;113(4):1548–1553. doi: 10.1111/j.1476-5381.1994.tb17172.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Brugnara C., de Franceschi L., Alper S. L. Inhibition of Ca(2+)-dependent K+ transport and cell dehydration in sickle erythrocytes by clotrimazole and other imidazole derivatives. J Clin Invest. 1993 Jul;92(1):520–526. doi: 10.1172/JCI116597. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Carroll M. A., Garcia M. P., Falck J. R., McGiff J. C. 5,6-epoxyeicosatrienoic acid, a novel arachidonate metabolite. Mechanism of vasoactivity in the rat. Circ Res. 1990 Nov;67(5):1082–1088. doi: 10.1161/01.res.67.5.1082. [DOI] [PubMed] [Google Scholar]
  6. Corriu C., Félétou M., Canet E., Vanhoutte P. M. Inhibitors of the cytochrome P450-mono-oxygenase and endothelium-dependent hyperpolarizations in the guinea-pig isolated carotid artery. Br J Pharmacol. 1996 Feb;117(4):607–610. doi: 10.1111/j.1476-5381.1996.tb15233.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Edwards G., Weston A. H. The pharmacology of ATP-sensitive potassium channels. Annu Rev Pharmacol Toxicol. 1993;33:597–637. doi: 10.1146/annurev.pa.33.040193.003121. [DOI] [PubMed] [Google Scholar]
  8. Fulton D., Mahboubi K., McGiff J. C., Quilley J. Cytochrome P450-dependent effects of bradykinin in the rat heart. Br J Pharmacol. 1995 Jan;114(1):99–102. doi: 10.1111/j.1476-5381.1995.tb14911.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Fulton D., McGiff J. C., Quilley J. Contribution of NO and cytochrome P450 to the vasodilator effect of bradykinin in the rat kidney. Br J Pharmacol. 1992 Nov;107(3):722–725. doi: 10.1111/j.1476-5381.1992.tb14513.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Fulton D., McGiff J. C., Quilley J. Role of K+ channels in the vasodilator response to bradykinin in the rat heart. Br J Pharmacol. 1994 Nov;113(3):954–958. doi: 10.1111/j.1476-5381.1994.tb17085.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Garland C. J., Plane F., Kemp B. K., Cocks T. M. Endothelium-dependent hyperpolarization: a role in the control of vascular tone. Trends Pharmacol Sci. 1995 Jan;16(1):23–30. doi: 10.1016/s0165-6147(00)88969-5. [DOI] [PubMed] [Google Scholar]
  12. Gebremedhin D., Ma Y. H., Falck J. R., Roman R. J., VanRollins M., Harder D. R. Mechanism of action of cerebral epoxyeicosatrienoic acids on cerebral arterial smooth muscle. Am J Physiol. 1992 Aug;263(2 Pt 2):H519–H525. doi: 10.1152/ajpheart.1992.263.2.H519. [DOI] [PubMed] [Google Scholar]
  13. Harder D. R., Campbell W. B., Roman R. J. Role of cytochrome P-450 enzymes and metabolites of arachidonic acid in the control of vascular tone. J Vasc Res. 1995 Mar-Apr;32(2):79–92. doi: 10.1159/000159080. [DOI] [PubMed] [Google Scholar]
  14. Hecker M., Bara A. T., Bauersachs J., Busse R. Characterization of endothelium-derived hyperpolarizing factor as a cytochrome P450-derived arachidonic acid metabolite in mammals. J Physiol. 1994 Dec 1;481(Pt 2):407–414. doi: 10.1113/jphysiol.1994.sp020449. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Hu S., Kim H. S. Activation of K+ channel in vascular smooth muscles by cytochrome P450 metabolites of arachidonic acid. Eur J Pharmacol. 1993 Jan 12;230(2):215–221. doi: 10.1016/0014-2999(93)90805-r. [DOI] [PubMed] [Google Scholar]
  16. Högestätt E. D., Andersson K. E., Edvinsson L. Mechanical properties of rat cerebral arteries as studied by a sensitive device for recording of mechanical activity in isolated small blood vessels. Acta Physiol Scand. 1983 Jan;117(1):49–61. doi: 10.1111/j.1748-1716.1983.tb07178.x. [DOI] [PubMed] [Google Scholar]
  17. Kalsner S., Nickerson M., Boyd G. N. Selective blockade of potassium-induced contractions of aortic strips by beta-diethylaminoethyl-diphenylpropylacetate (SKF 525A). J Pharmacol Exp Ther. 1970 Sep;174(3):500–508. [PubMed] [Google Scholar]
  18. Komori K., Vanhoutte P. M. Endothelium-derived hyperpolarizing factor. Blood Vessels. 1990;27(2-5):238–245. doi: 10.1159/000158815. [DOI] [PubMed] [Google Scholar]
  19. Lischke V., Busse R., Hecker M. Selective inhibition by barbiturates of the synthesis of endothelium-derived hyperpolarizing factor in the rabbit carotid artery. Br J Pharmacol. 1995 Jul;115(6):969–974. doi: 10.1111/j.1476-5381.1995.tb15905.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Murray M., Reidy G. F. Selectivity in the inhibition of mammalian cytochromes P-450 by chemical agents. Pharmacol Rev. 1990 Jun;42(2):85–101. [PubMed] [Google Scholar]
  21. Petersson J., Zygmunt P. M., Brandt L., Högestätt E. D. Substance P-induced relaxation and hyperpolarization in human cerebral arteries. Br J Pharmacol. 1995 Jul;115(6):889–894. doi: 10.1111/j.1476-5381.1995.tb15893.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Pfister S. L., Falck J. R., Campbell W. B. Enhanced synthesis of epoxyeicosatrienoic acids by cholesterol-fed rabbit aorta. Am J Physiol. 1991 Sep;261(3 Pt 2):H843–H852. doi: 10.1152/ajpheart.1991.261.3.H843. [DOI] [PubMed] [Google Scholar]
  23. Rosolowsky M., Campbell W. B. Role of PGI2 and epoxyeicosatrienoic acids in relaxation of bovine coronary arteries to arachidonic acid. Am J Physiol. 1993 Feb;264(2 Pt 2):H327–H335. doi: 10.1152/ajpheart.1993.264.2.H327. [DOI] [PubMed] [Google Scholar]
  24. Shak S., Reich N. O., Goldstein I. M., Ortiz de Montellano P. R. Leukotriene B4 omega-hydroxylase in human polymorphonuclear leukocytes. Suicidal inactivation by acetylenic fatty acids. J Biol Chem. 1985 Oct 25;260(24):13023–13028. [PubMed] [Google Scholar]
  25. Taylor W. J., Wolf A., Young J. M. The interaction of amine local anaesthetics with muscarinic receptors. Br J Pharmacol. 1980;71(1):327–335. doi: 10.1111/j.1476-5381.1980.tb10943.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. Triggle C. R., Swamy V. C., Triggle D. J. Calcium antagonists and contractile responses in rat vas deferens and guinea pig ileal smooth muscle. Can J Physiol Pharmacol. 1979 Aug;57(8):804–818. doi: 10.1139/y79-124. [DOI] [PubMed] [Google Scholar]
  27. Villalobos C., Fonteriz R., López M. G., García A. G., García-Sancho J. Inhibition of voltage-gated Ca2+ entry into GH3 and chromaffin cells by imidazole antimycotics and other cytochrome P450 blockers. FASEB J. 1992 Jun;6(9):2742–2747. doi: 10.1096/fasebj.6.9.1319362. [DOI] [PubMed] [Google Scholar]
  28. Zou A. P., Imig J. D., Kaldunski M., Ortiz de Montellano P. R., Sui Z., Roman R. J. Inhibition of renal vascular 20-HETE production impairs autoregulation of renal blood flow. Am J Physiol. 1994 Feb;266(2 Pt 2):F275–F282. doi: 10.1152/ajprenal.1994.266.2.F275. [DOI] [PubMed] [Google Scholar]
  29. Zou A. P., Ma Y. H., Sui Z. H., Ortiz de Montellano P. R., Clark J. E., Masters B. S., Roman R. J. Effects of 17-octadecynoic acid, a suicide-substrate inhibitor of cytochrome P450 fatty acid omega-hydroxylase, on renal function in rats. J Pharmacol Exp Ther. 1994 Jan;268(1):474–481. [PubMed] [Google Scholar]
  30. Zygmunt P. M., Grundemar L., Högestätt E. D. Endothelium-dependent relaxation resistant to N omega-nitro-L-arginine in the rat hepatic artery and aorta. Acta Physiol Scand. 1994 Sep;152(1):107–114. doi: 10.1111/j.1748-1716.1994.tb09789.x. [DOI] [PubMed] [Google Scholar]
  31. Zygmunt P. M., Högestätt E. D. Role of potassium channels in endothelium-dependent relaxation resistant to nitroarginine in the rat hepatic artery. Br J Pharmacol. 1996 Apr;117(7):1600–1606. doi: 10.1111/j.1476-5381.1996.tb15327.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  32. Zygmunt P. M., Waldeck K., Högestätt E. D. The endothelium mediates a nitric oxide-independent hyperpolarization and relaxation in the rat hepatic artery. Acta Physiol Scand. 1994 Dec;152(4):375–384. doi: 10.1111/j.1748-1716.1994.tb09819.x. [DOI] [PubMed] [Google Scholar]

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