| Abstract |
Phospholipase C (PLC)β has a role in saliva secretion by controlling intracellular Ca2+ via its product, IP3. The
present study was attempted to localize PLCβ isoforms in mouse salivary glands in situ. A single major band was
detected for PLCβ3 in immunoblots of the parotid and sublingual glands (PG, SLG), while no such band was seen
in the submandibular gland (SMG). No bands were detected for PLCβ1 or 4 in the three glands. In immuno-light
microscopy of PG and SLG, substantial immunoreactivity for PLCβ3 was seen in the cytoplasm including the
plasmalemma of almost all ductal cells, while no distinct immunoreactivity was discerned in most acinar cells
except for sublingual demilune cells. Numerous ductal cells exhibited higher immunoreactivity for PLCβ3 in
their apical/supranuclear cell domain including the plasmalemma than in the basal/infranuclear domain, indicating
an apico-basal polarity. In immuno-gold electron microscopy of PG ducts and SLG ducts and demilunes,
most gold particles were found in association with plasma membranes as well as various intracellular membranes,
most of which formed small oblong or flattened vesicles and vacuoles. A few particles were seen without
association with any membranous structures. The present finding supports the previous physio-pharmacological
result that Ca2+-signaling proteins as well as initial intracellular Ca2+ changes occur in the apical cell domain
including the plasma membranes of the exocrine cells. |
Publication
Journal Publication
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