HISTOLOGY AND HISTOPATHOLOGY

Cellular and Molecular Biology



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