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An ultracytochemical study on the dynamics of alkaline phosphatase-positive
granules in rat neutrophils
X. Jiang1, T. Kobayashi1, P.C. Nahirney2, E. García
del Saz1 and H. Seguchi1
1Department of Anatomy and Cell Biology, Kochi Medical
School, Kochi, Japan and 2Department of Anatomy, Faculty of Medicine, University
of British Columbia, Vancouver, Canada
Offprint requests to: Dr. H.
Seguchi, Department of Anatomy and Cell Biology, Kochi Medical School, Kohasu,
Okoh-cho Nankoku, Kochi, 783, Japan
Summary. Alkaline phosphatase
(ALPase) activity was examined by cerium-based ultracytochemistry in isolated
rat neutrophils following stimulation with phorbol myristate acetate (PMA)
or N-formyl-methionyl-leucyl-phenylalanine (fMLP). In control neutrophils,
low levels of ALPase activity were detected in small tubular and spherical
compartments distributed throughout the cytoplasm. Neutrophils stimulated
for 2.5, 5, 15, and 30 min with 50 ng/ml PMA or 10-7 M fMLP displayed a
time-dependent increase in ALPase activity. At 2.5 min, an increase in activity
was first identified in compartments that were aggregated in the central
regions of the cell. By 15 min, a dense precipitate was seen in tubular
or elongated bead-like structures that extended to and made contact with
the plasma membrane. Large enzyme-positive vacuoles were also observed in
regions near the plasma membrane. At the longer stimulation times, a fine
precipitate was present on the cell surface of the neutrophil in regions
where subplasmalemmal ALPase activity was present. The results of this study
indicate that an increase in activity and a redistribution of ALPase-positive
structures occurs in neutrophils in response to stimulation with PMA and
fMLP. It is likely that these compartments are latent pools of ALPase which,
upon stimulation, fuse and mobilize the enzyme activity to the cell surface.
Histol Histopathol 13, 57-65 (1998)
Key words: Neutrophil, Alkaline
phosphatase, Upregulation, Cytochemistry, Rat
DOI: 10.14670/HH-13.57
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