Effects of cytochrome P450 inhibitors on agonist-induced Ca2+ responses and production of NO and PGI2 in vascular endothelial cells.
Production of endothelium-dependent vascular relaxing factors, such as nitric oxide (NO) and prostaglandin I2 (PGI2), and endothelium-derived hyperpolarizing factor (EDHF), is regulated in part by changes in intracellular Ca2+ concentration ([Ca2+]i) in vascular endothelial cells (ECs). Cytochrome P450 (CYP), shown to mediate endothelium-dependent hyperpolarization via epoxyeicosatrienoic acids, is one of the candidates for EDHF. In this study we tested the hypotheses that CYP might be involved in EC Ca2+ signaling and that CYP activity might be linked with production of vasodilating factors other than EDHF. To this end, structurally different CYP inhibitors including SKF 525A, econazole and miconazole were tested on primary cultured porcine aortic endothelial cells. Intracellular Ca2+ concentration was measured using the fluorescent Ca2+ indicator fura-2/AM. Bradykinin (BK, 10 nM) and thapsigargin (TG 1 microM) provoked large biphasic increases in [Ca2+], which consist of Ca2+ release from intracellular stores and transplasmalemmal Ca2+ entry. SKF 525A dose-dependently (30-100 microM) inhibited BK- and TG-stimulated Ca2+ entry, but not intracellular Ca2+ store release. Econazole (10 microM) and miconazole (10 microM) had the same effect as SKF 525A on the Ca2+ entry. SKF 525A also dose-dependently inhibited BK-stimulated production of NO and PGI2, assessed by measuring cGMP and 6-keto-PGF(1alpha) concentration. These data suggest that, in addition to its regulation of EDHF production, CYP also contributes to the regulation of other endothelium-dependent vasorelaxing factors by modifying EC Ca2+ signaling.
Takeuchi
Kazuhiko
K
Department of Internal Medicine III, Hamamatsu University School of Medicine, Handayama, Hamamatsu, Japan.
Watanabe
Hiroshi
H
Tran
Quang-Kim
QK
Ozeki
Mariko
M
Uehara
Akihiko
A
Katoh
Hideki
H
Satoh
Hiroshi
H
Terada
Hajime
H
Ohashi
Kyoichi
K
Hayashi
Hideharu
H
D015121:6-Ketoprostaglandin F1 alpha / Q000378:metabolism; D000818:Animals; D000935:Antifungal Agents / Q000494:pharmacology; D001920:Bradykinin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D006152:Cyclic GMP / Q000378:metabolism; D065607:Cytochrome P-450 Enzyme Inhibitors; D004305:Dose-Response Relationship, Drug; D004464:Econazole / Q000494:pharmacology; D042783:Endothelial Cells / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology* / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D011464:Epoprostenol / Q000378:metabolism*; D008825:Miconazole / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism*; D011335:Proadifen / Q000494:pharmacology; D044062:Prostaglandins I / Q000378:metabolism; D015398:Signal Transduction; D013552:Swine; D019284:Thapsigargin / Q000494:pharmacology; D013997:Time Factors
D000935:Antifungal Agents; D065607:Cytochrome P-450 Enzyme Inhibitors; D004791:Enzyme Inhibitors; D044062:Prostaglandins I; D009569:Nitric Oxide; D015121:6-Ketoprostaglandin F1 alpha; D019284:Thapsigargin; D004464:Econazole; D008825:Miconazole; D011335:Proadifen; D011464:Epoprostenol; D006152:Cyclic GMP; D001920:Bradykinin; D002118:Calcium