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    Please use this identifier to cite or link to this item: https://ir.fy.edu.tw:8080/ir/handle/987654321/9516


    Title: Differential Regulation of Ca2+ Influx by FMLP and PAF in Human Neutrophils: Possible Involvement of Store-Operated Ca2+ Channel.
    Authors: Lee-Wei Chen;Ai-Yu Shen;Jin-Shyr Chen;Sheng-Nan Wu.
    Contributors: 輔英科技大學 物理治療系
    Keywords: Neutrophil;Platelet activating factor;Calcium ion;Regulation(control);Loperamide;Activator;Protein kinase C;3',5'-GMP;Biological effect;Physiology;Human;Transferases;Enzyme
    Date: 2000-03-01
    Issue Date: 2010-11-10 09:42:42 (UTC+8)
    Abstract: Calcium (Ca2+) influx into human polymorphonuclear cells (PMNs) in response to N-formyl-Met-Leu-Phe (fMLP) and platelet-activating factor (PAF) stimulation was studied. Whole blood was taken by venous puncture from healthy human volunteers. PMNs were isolated, diluted, and incubated with 2 μM fura-2 AM. The cytosolic free calcium concentration, [Ca2+]i, in human neutrophils was determined by microfluorometry. We found that the net area under the fMLP- or PAF-induced [Ca2+]i rise curve in Ca2+-free medium decreased to 75% or 30% of the area under the curve in Ca2+ medium. Treatment of PMNs with phorbol myristate acetate (PMA), a protein kinase C activator, completely abolished the intracellular Ca2+ level stimulated by PAF, but not the intracellular Ca2+ level stimulated by fMLP. Treatment of PMNs with PAF did not abolish the intracellular Ca2+ level elevation stimulated by fMLP. In addition, treatment of PMNs with fMLP did not abolish intracellular Ca2+ level elevation stimulated by PAF. Loperamide, a positive modulator for store-operated calcium (SOC) channels, elicited an increase in intracellular calcium after the activation of SOC channels stimulated by fMLP or PAF. After the addition of guanosine 3',5'-cyclic monophosphate, N2,2'-O-Dibutyryl-, sodium salt (db-cGMP), the initial increase of PAF- or fMLP-induced PMNs intracellular Ca2+ fluorescences was well preserved, but the slope and the peak height of fluorescence curves declined compared with the curves without db-cGMP. In conclusion, we found that PAF and fMLP regulate the Ca2+ influx of PMNs in different ways. Most of the PAF-induced [Ca2+]i rise resulted from Ca2+ influx, and most of the fMLP-induced [Ca2+]i elevation resulted from intracellular stores release. The initial mobilization of intracellular Ca2+ stores in PAF-stimulated signals is mediated by protein kinase C (PKC) phosphorylation, but not in fMLP-stimulated route. SOC channels are present and important in the fMLP- or PAF-induced PMNs Ca2+ influx. There was no apparent cross-regulation between PAF- and fMLP-stimulated intracellular Ca2+ influx.
    Relation: Shock. 13(3),175-182
    Appears in Collections:[物理治療系] 期刊論文

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