Ca2+ dynamics in salivary acinar cells: distinct morphology of the acinar lumen underlies near-synchronous global Ca2+ responses

We have shown that endocytosis at the apical plasma membrane of pancreatic acinar cells is regulated by the pH of the acinar lumen and is associated with cleavage of GP2, a glycosyl phosphatidylinositol-anchored protein. The aim of this study was to determine the transduction pathway by which endocytosis is activated. Apical endocytosis was studied in rat pancreatic acini by prestimulation with cholecystokinin followed by measurement of horseradish peroxidase (HRP) uptake. Lanthanum, staurosporine, and forskolin had no effect on HRP uptake. Cytochalasin D significantly inhibited endocytosis, indicating a dependence on actin filament integrity. Genistein and the specific tyrphostin inhibitor B42 also inhibited HRP uptake, implicating tyrosine kinases in the regulation of HRP uptake. With the use of an Src kinase-specific substrate, Src kinase activity was temporally related to activation of endocytosis. The tyrosine-dependent phosphorylation of an 85-kDa substrate in both rat and mouse pancreatic acini correlated with Src kinase activation and pH-dependent regulation of HRP uptake. These results indicate that apical endocytosis in acinar cells is associated with tyrosine kinase activation and is dependent on the actin cytoskeleton.

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Acinar lumen pH regulates endocytosis, but not exocytosis, at the apical plasma membrane of pancreatic acinar cells

European Journal of Cell Biology ◽

10.1016/s0171-9335(98)80057-5 ◽

1998 ◽

Vol 75 (2) ◽

pp. 153-162 ◽

Cited By ~ 30

Author(s):

Steven D. Freedman ◽

Horst F. Kern ◽

George A. Scheele

Keyword(s):

Plasma Membrane ◽

Acinar Cells ◽

Pancreatic Acinar Cells ◽

Apical Plasma Membrane ◽

Acinar Lumen

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Ultrastructure of the Parotid Gland of the Nine-Banded Armadillo

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100080626 ◽

1977 ◽

Vol 35 ◽

pp. 640-641

Author(s):

J. R. Ruby

Keyword(s):

Endoplasmic Reticulum ◽

Parotid Gland ◽

Periodic Acid ◽

Acinar Cells ◽

Duct System ◽

Parotid Glands ◽

Dasypus Novemcinctus ◽

Anterior Portion ◽

Periodic Acid Schiff ◽

Thin Sections

Parotid glands were obtained from five adult (four male and one female) armadillos (Dasypus novemcinctus) which were perfusion-fixed. The glands were located in a position similar to that of most mammals. They extended interiorly to the anterior portion of the submandibular gland.In the light microscope, it was noted that the acini were relatively small and stained strongly positive with the periodic acid-Schiff (PAS) and alcian blue techniques, confirming the earlier results of Shackleford (1). Based on these qualities and other structural criteria, these cells have been classified as seromucous (2). The duct system was well developed. There were numerous intercalated ducts and intralobular striated ducts. The striated duct cells contained large amounts of PAS-positive substance.Thin sections revealed that the acinar cells were pyramidal in shape and contained a basally placed, slightly flattened nucleus (Fig. 1). The rough endoplasmic reticulum was also at the base of the cell.

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The ultrastructure of acinar cells in the external orbital gland of young and old male rats

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100082248 ◽

1978 ◽

Vol 36 (2) ◽

pp. 276-277

Author(s):

R. Carriere

Keyword(s):

Young Adulthood ◽

Acinar Cells ◽

Cell Number ◽

Male Rats ◽

Polyploid Cell ◽

Secretory Cells ◽

Age Changes ◽

Albino Rat ◽

Golgi Membranes ◽

Diploid Cells

The external orbital gland of the albino rat exhibits both sexual dimorphism and histological age changes. In males, many cells attain a remarkable degree of polyploidy and an increase of polyploid cell number constitutes the major age change until young adulthood. The acini of young adults have a small lumen and are composed of tall serous cells. Subsequently, many acini acquire a larger lumen with an irregular outline while numerous vacuoles accumulate throughout the secretory cells. At the same time, vesicular acini with a large lumen surrounded by pale-staining low cuboidal diploid cells begin to appear and their number increases throughout old age. The fine structure of external orbital glands from both sexes has been explored and in considering acinar cells from males, emphasis was given to the form of the Golgi membranes and to nuclear infoldings of cytoplasmic constituents.

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Further Studies on the Ultrastructure of Harderian Gland in Adult Rats

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100051451 ◽

1974 ◽

Vol 32 ◽

pp. 288-289

Author(s):

Alfredo Feria-Velasco ◽

Guadalupe Tapia-Arizmendi

Keyword(s):

Fine Structure ◽

Domestic Fowl ◽

Animal Species ◽

Acinar Cells ◽

Harderian Gland ◽

Myoepithelial Cells ◽

The Other ◽

Albino Rats ◽

Adult Rats ◽

Cell Components

The fine structure of the Harderian gland has been described in some animal species (hamster, rabbit, mouse, domestic fowl and albino rats). There are only two reports in the literature dealing on the ultrastructure of rat Harderian gland in adult animals. In one of them the author describes the myoepithelial cells in methacrylate-embbeded tissue, and the other deals with the maturation of the acinar cells and the formation of the secretory droplets. The aim of the present work is to analize the relationships among the acinar cell components and to describe the two types of cells located at the perifery of the acini.

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