Loy F, Puxeddu R, Isola M, Loffredo F, Riva A, Testa Riva F.
Morphological alterations induced by cytochalasin D on serous
cells of human submandibular gland in basal and stimulated
conditions.
Ital J Anat Embryol. 2005;110(2 Suppl 1):65-70
Department of Cytomorphology, University of Cagliari,
Cagliari, Italy.
Cytochalasin D is a fungal toxin which binds to the
faster growing end of actin microfilament and inhibits actin
polymerization. By an in vitro incubation system of slices of
human submandibular glands obtained at surgery, we investigated
by light microscope (LM), transmission electron microscope
(TEM), and high resolution scanning electron microscope (HRSEM)
the morphological changes caused by Cytochalasin D on serous
cells. We studied the effects of the drug on secretory events
induced by isoproterenol (I) and carbachol (C). With LM,
following Cytochalasin D incubation, canaliculi were enlarged
and prominent vacuoles were seen throughout the cytoplasm. By
TEM, the vacuoles, which in many cases were in continuity with
the lumen, represented the distinctive feature of secretory
cells. With HRSEM, intercellular canaliculi, seen from their
cytoplasmic side, exhibited many small spherical bulges,
corresponding to the coated pits seen with TEM and indicating
that the retrieval of plasma membrane was arrested at an early
phase by the disruption of the actin cytoskeleton. In specimens
treated with secretagogues and Cytochalasin D a
consequence reported here for the first time was the presence of
dense granules within the vacuoles. The protrusions seen by
HRSEM on the cytoplasmic side of intercellular canaliculi,
following secretagogues stimulations, appeared peculiar to each
stimulants, even if combined with Cytochalasin D , suggesting
that besides actin filaments, other components, unaffected by
Cytochalasin D , also are involved in the process of exocytosis
and related phenomena.
PMID: 16101022 |
