title: Stimulation by leukotriene D4 of increases in the cytosolic concentration of calcium in dimethylsulfoxide-differentiated HL-60 cells.
abstract: The C6-sulfidopeptide leukotrienes C4 (LTC4) and D4 (LTD4) evoked increases in the cytosolic concentration of intracellular calcium ([Ca+2]i) in dimethylsulfoxide-differentiated HL-60 cells, as assessed by the fluorescence of quin-2. The increases in [Ca+2]i reached a peak within 15-90 s, attained 50% of the maximum level at 1.2 nM LTD4 and 60 nM LTC4, were greater in maximal magnitude for LTD4 than LTC4, and subsided in 5-7 min. Flow cytometric evaluation of the LTD4-induced increases in [Ca+2]i, reflected in increases in the fluorescence of intracellular indo-1, revealed that a mean of 77% of differentiated HL-60 cells responded, as contrasted with lesser increases in only 50% of undifferentiated HL-60 cells. The capacity of pretreatment of HL-60 cells with LTD4 to prevent subsequent responses of [Ca+2]i to LTC4 and LTD4, and the finding that the serine-borate inhibitor of conversion of LTC4 to LTD4 suppressed concurrently both LTC4-induced rises in [Ca+2]i and increases in adherence to Sephadex G-25 indicated that the responses of HL-60 cells to LTC4 required conversion to LTD4. That pertussis toxin and a chemical antagonist of LTD4 reduced the [Ca+2]i response suggested a dependence on LTD4 receptors. The LTD4-induced increases in [Ca+2]i were dependent on extracellular calcium and diminished by lanthanum, but not affected by nifedipine nor associated with changes in membrane potential, as measured with the fluorescent probe 3,3'-dipentyloxacarbocyanine. Thus, the increase in [Ca+2]i in HL-60 cells, which is coupled to an increase in adherence, appears to involve LTD4 receptor-specific and voltage-independent calcium channels in the plasma membrane.
mesh_terms: D000634:Aminoquinolines; D002118:Calcium / Q000378:metabolism*; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D004121:Dimethyl Sulfoxide / Q000494:pharmacology*; D005453:Fluorescence; D006801:Humans; D007211:Indoles; D015470:Leukemia, Myeloid, Acute / Q000378:metabolism*; D013189:SRS-A / Q000494:pharmacology*
chemical_list: D000634:Aminoquinolines; D007211:Indoles; D013189:SRS-A; C048960:indo-1; C035739:Quin2; D002118:Calcium; D004121:Dimethyl Sulfoxide