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Morphological study of rat mast cells stimulated with compound 48/80 at different temperatures
1First Department of Medicine, Yamanashi Medical University, Japan.
Abstract:
Changes of mast cells stimulated with compound 48/80 were morphologically investigated at different temperatures. Peritoneal mast cells of male rats were stimulated in vitro at 4 or 17 degrees C. At 17 degrees C, mast cells stimulated for 10 s gave decreased fluorescent reactions for phalloidin. At 30 s stimulation, they showed typical exocytosis initiated by fusions of peripherally located secretory granules to the plasma membrane. In contrast, mast cells stimulated at 4 degrees C exhibited neither decrease of phalloidin reactions nor typical excytosis even after 30 s. It was inferred that the fusions were mediated by cytoplasmic elements, probably the actin filaments previously suggested to prevent release of secretory granules. Furthermore, the space between the perigranular membrane and granular contents was enlarged in some mast cells stimulated at 4 degrees C. The morphological changes suggested that equivocal events occurred also in the cytoplasm of these cells. The mast cells showed no typical exocytosis at 4 degrees C.
Insights
Low temperatures inhibit mast cell degranulation. Compound 48/80 stimulation at 4°C prevented actin-mediated exocytosis, unlike at 17°C, suggesting temperature-dependent cellular mechanisms.
Area of Science:
- Cell Biology
- Immunology
Background:
- Mast cells are crucial immune cells involved in allergic reactions and inflammation.
- Compound 48/80 is a known inducer of mast cell degranulation.
Purpose of the Study:
- To investigate the morphological changes of mast cells stimulated with compound 48/80 at different temperatures.
- To elucidate the role of temperature in mast cell degranulation and exocytosis.
Main Methods:
- Peritoneal mast cells from male rats were isolated and stimulated in vitro with compound 48/80.
- Cells were incubated at two different temperatures: 4°C and 17°C.
- Morphological changes, including phalloidin reactions and exocytosis, were observed using microscopy.
Main Results:
- At 17°C, mast cells showed decreased phalloidin reactions and typical exocytosis after 30s stimulation.
- At 4°C, mast cells exhibited no decrease in phalloidin reactions or typical exocytosis, even after 30s.
- Enlargement of the space between perigranular membrane and granular contents was observed at 4°C.
Conclusions:
- Temperature significantly impacts mast cell degranulation and exocytosis.
- Actin filaments likely mediate exocytosis, and their function is temperature-dependent.
- Low temperatures (4°C) inhibit compound 48/80-induced mast cell degranulation, suggesting a critical role for cytoplasmic elements in granule release.