Mechanisms of miconazole-induced rise in cytoplasmic calcium concentrations in Madin Darby canine kidney (MDCK) cells.
The effect of miconazole on intracellular calcium levels ([Ca2+]i) in Madin Darby canine kidney (MDCK) cells was studied using fura-2 as the Ca2+ indicator. Miconazole increased [Ca2+]i dose-dependently at concentrations of 5-100 microM. The [Ca2+]i transient consisted of an initial rise, a gradual decay and an elevated plateau (220 s after addition of the drug). Removal of extracellular Ca2+ partly reduced the miconazole response. Mn2+ quench of fura-2 fluorescence confirmed that miconazole induced Ca2+ influx. The miconazole-sensitive intracellular Ca2+ store overlapped with that sensitive to thapsigargin, an inhibitor of the endoplasmic reticulum Ca2+ pump, because 20 microM miconazole depleted the thapsigargin (1 microM)-sensitive store, and conversely, thapsigargin abolished miconazole-induced internal Ca2+ release. Miconazole (20-50 microM) partly inhibited the capacitative Ca2+ entry induced by 1 microM thapsigargin, measured by depleting intracellular Ca2+ store in Ca(2+)-free medium followed by addition of 10 mM CaCl2. Miconazole induced capacitative Ca2+ entry on its own. Pretreatment with 0.1 mM La3+ partly inhibited 20 microM miconazole-induced Mn2+ quench of fura-2 fluorescence and [Ca2+]i rise, suggesting that miconazole induced Ca2+ influx via two pathways separable by 0.1 mM La3+. Miconazole-induced internal Ca2+ release was not altered when the cytosolic level of inositol 1,4,5-trisphosphate (IP3) was substantially inhibited by the phospholipase C inhibitor U73122.
Jan
C R
CR
Department of Medical Education and Research, Veterans General Hospital-Kaohsiung, Taiwan. crjan@isca.vghks.gov.tw
Tseng
C J
CJ
D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000502:physiology; D020013:Calcium Signaling / Q000187:drug effects; D002412:Cations; D002460:Cell Line; D003593:Cytoplasm / Q000187:drug effects / Q000378:metabolism; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004553:Electric Conductivity; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D004963:Estrenes / Q000494:pharmacology; D015544:Inositol 1,4,5-Trisphosphate / Q000096:biosynthesis; D007668:Kidney / Q000166:cytology; D007811:Lanthanum / Q000494:pharmacology; D008825:Miconazole / Q000494:pharmacology*; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D011760:Pyrrolidinones / Q000494:pharmacology; D019284:Thapsigargin / Q000494:pharmacology; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors
D002412:Cations; D004963:Estrenes; D010726:Phosphodiesterase Inhibitors; D011760:Pyrrolidinones; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; D019284:Thapsigargin; D007811:Lanthanum; D008825:Miconazole; D015544:Inositol 1,4,5-Trisphosphate; D010738:Type C Phospholipases; D002118:Calcium