scholarly journals Calcium metabolism and amylase release in rat parotid acinar cells

1976 ◽  
Vol 160 (3) ◽  
pp. 547-564 ◽  
Author(s):  
P Kanagasuntheram ◽  
P J Randle

1. A method is described for the isolation of rat parotid acinar cells by controlled digestion of the gland with trypsin followed by collagenase. As judged by Trypan Blue exclusion, electron microscopy, water, electrolyte and ATP concentrations and release of amylase and lactate dehydrogenase, the cells are morphologically and functionally intact. 2. A method was developed for perifusion of acinar cells by embedding them in Sephadex G-10. Release of amylase was stimulated by adrenaline (0.1-10μM), isoproternol (1 or 10 μM), phenylephrine (1 μM), carbamoylcholine (0.1 or 1 μM), dibutyryl cycle AMP (2 MM), 3-isobutyl-1-methylxanthine (1mM) and ionophore A23187. The effects of phenylephrine, carbamoylcholine and ionophore A23187 required extracellular Ca2+, whereas the effects of adrenaline and isoproterenol did not. 3. The incorporation of 45Ca into parotid cells showed a rapidly equilibrating pool (1-2 min) corresponding to 15% of total Ca2+ and a slowly equilibrating pool (> 3h) of probably a similar dimension. Cholinergic and α-adrenergic effectors and ionophore A23187 and 2,4-dinitrophenol increased the rate of incorporation of 45Ca into a slowly equilibrating pool, whereas β-adrenergic effectors and dibutyryl cyclic AMP were inactive. 4. The efflux of 45Ca from cells into Ca2+-free medium was inhibited by phenylephrine and carbamoylcholine and accelerated by isoproterenol, adrenaline (β-adrenergic effect), dibutyryl cyclic AMP and ionophore A23187. 5. A method was developed for the measurement of exchangeable 45Ca in mitochondria in parotid pieces. Incorporation of 45Ca into mitochondria was decreased by isoproterenol, dibutyryl cyclic AMP or 2,4-dinitrophenol, increased by adrenaline, and not changed significantly by phenylephrine or carbamoylcholine. Release of 45Ca from mitochondria in parotid pieced incubated in a Ca2+-free medium was increased by isoproterenol, adrenaline, dibutyryl cyclic AMP or 2,4-dinitrophenol and unaffected by phenylephrine or carbamoylcholine. 6. These findings are compatible with a role for Ca2+ as a mediator of amylase-secretory responses in rat parotid acinar cells, but no definite conclusions about its role can be drawn in the absence of knowledge of the molecular mechanisms involved, their location, and free Ca2+ concentration in appropriate cell compartment(s).

2012 ◽  
Vol 120 (2) ◽  
pp. 123-131 ◽  
Author(s):  
Akane Imai ◽  
Sumio Yoshie ◽  
Maiko Haga-Tsujimura ◽  
Tomoko Nashida ◽  
Hiromi Shimomura

1981 ◽  
Vol 240 (5) ◽  
pp. C189-C192 ◽  
Author(s):  
E. L. Watson ◽  
C. J. Farnham ◽  
J. Friedman ◽  
W. Farnham

Isolated mouse parotid acinar cells (acini) were prepared by enzyme digestion, divalent cation depletion, and mechanical shearing. Acini were found to be morphologically intact, i.e., 95% viable as judged by trypan blue exclusion. Amylase release by the cholinergic agonist carbachol, by the beta-adrenergic agonist isoproterenol, and by monensin was similar to responses obtained in mouse parotid fragments. Monensin-stimulated amylase release was associated with enhanced 22Na+ uptake and 45Ca2+ efflux; monensin did not affect 45Ca2+ uptake. In the absence of extracellular Na+, the response to monensin (50 microM) was reduced from 162 +/- 33.5 to 12.4 +/- 0.5%; monensin also failed to stimulate 45Ca2+ efflux. Similar results were obtained with isoproterenol (10(-6) M). The results suggest that Na+ ions may play a role in amylase release possibly by releasing Ca2+ from internal stores.


1994 ◽  
Vol 64 ◽  
pp. 318
Author(s):  
Junichi Yamane ◽  
Yoshiko Moriya ◽  
Shunsuke Furuyama ◽  
Hiroshi Sugiya

2009 ◽  
Vol 296 (6) ◽  
pp. G1382-G1390 ◽  
Author(s):  
Keitaro Satoh ◽  
Miwako Matsuki-Fukushima ◽  
Bing Qi ◽  
Ming-Yu Guo ◽  
Takanori Narita ◽  
...  

Myristoylated alanine-rich C kinase substrate (MARCKS) is known as a major cellular substrate for protein kinase C (PKC). MARCKS has been implicated in the regulation of brain development and postnatal survival, cellular migration and adhesion, as well as phagocytosis, endocytosis, and exocytosis. The involvement of MARCKS phosphorylation in secretory function has been reported in Ca2+-mediated exocytosis. In rat parotid acinar cells, the activation of β-adrenergic receptors provokes exocytotic amylase release via accumulation of intracellular cAMP levels. Here, we studied the involvement of MARCKS phosphorylation in the cAMP-dependent amylase release in rat parotid acinar cells. MARCKS protein was detected in rat parotid acinar cells by Western blotting. The β-adrenergic agonist isoproterenol (IPR) induced MARCKS phosphorylation in a time-dependent manner. Translocation of a part of phosphorylated MARCKS from the membrane to the cytosol and enhancement of MARCKS phosphorylation at the apical membrane site induced by IPR were observed by immunohistochemistry. H89, a cAMP-dependent protein kinase (PKA) inhibitor, inhibited the IPR-induced MARCKS phosphorylation. The PKCδ inhibitor rottlerin inhibited the IPR-induced MARCKS phosphorylation and amylase release. IPR activated PKCδ, and the effects of IPR were inhibited by the PKA inhibitors. A MARCKS-related peptide partially inhibited the IPR-induced amylase release. These findings suggest that MARCKS phosphorylation via the activation of PKCδ, which is downstream of PKA activation, is involved in the cAMP-dependent amylase release in parotid acinar cells.


1996 ◽  
Vol 41 (6) ◽  
pp. 547-551 ◽  
Author(s):  
Taishin Takuma ◽  
Toshihiko Yajima ◽  
Tokuro Ichida

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