Co-expression of mCysLT1 receptors and IK channels in Xenopus laevis oocytes elicits LTD4-stimulated IK current, independent of an increase in [Ca2+]i.
Addition of LTD4 (10 nM) to Xenopus laevis oocytes expressing the mCysLT1 receptor together with hBK or hIK channels resulted in the activation of both channels secondary to an LTD4-induced increase in [Ca2+]i. In addition, the hIK channel is activated by low concentrations of LTD4 (<0.1 nM), which did not result in any increase in [Ca2+]i. Even though activation of hIK by low concentrations of LTD4 was independent of an increase in [Ca2+]i, a certain "permissive" level of [Ca2+]i was required for its activation, since buffering of intracellular Ca2+ by EGTA completely abolished the response to LTD4. Neither hTBAK1 nor hTASK2 was activated following stimulations with LTD4 (0.1 and 100 nM).
Wulff
Tune
T
Biochemical Department, August Krogh Institute, University of Copenhagen, Universitetsparken 13, DK-2100 Copenhagen, Denmark.
Hougaard
Charlotte
C
Klaerke
Dan A
DA
Hoffmann
Else K
EK
D000818:Animals; D002118:Calcium / Q000032:analysis / Q000378:metabolism; D002413:Cations, Divalent; D002460:Cell Line / Q000187:drug effects; D016207:Cytokines / Q000096:biosynthesis* / Q000235:genetics; D004533:Egtazic Acid; D006801:Humans; D006863:Hydrogen-Ion Concentration; D051036:Large-Conductance Calcium-Activated Potassium Channels; D017998:Leukotriene D4 / Q000037:antagonists & inhibitors / Q000494:pharmacology; D008565:Membrane Proteins / Q000819:agonists / Q000096:biosynthesis* / Q000235:genetics; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism*; D015221:Potassium Channels / Q000032:analysis; D024681:Potassium Channels, Calcium-Activated / Q000096:biosynthesis / Q000235:genetics; D024683:Potassium Channels, Tandem Pore Domain; D018075:RNA, Complementary / Q000494:pharmacology; D018077:Receptors, Leukotriene / Q000819:agonists / Q000096:biosynthesis* / Q000235:genetics; D014162:Transfection; D014982:Xenopus laevis
D002413:Cations, Divalent; D016207:Cytokines; C090444:IK protein, human; C410295:KCNK5 protein, human; D051036:Large-Conductance Calcium-Activated Potassium Channels; D008565:Membrane Proteins; D015221:Potassium Channels; D024681:Potassium Channels, Calcium-Activated; D024683:Potassium Channels, Tandem Pore Domain; D018075:RNA, Complementary; D018077:Receptors, Leukotriene; D004533:Egtazic Acid; D017998:Leukotriene D4; C083169:leukotriene D4 receptor; D002118:Calcium