Role of calcium in exocrine pancreatic secretion. IV. Calcium movements in isolated acinar cells of rabbit pancreas

Renckens, Bernadet; Schrijen, J.J.; Swarts, H.G.P.; Pont, J.J.H.H.M. de; Bonting, S.L.

doi:10.1016/0304-4165(78)90102-2

Cited by 19 publications

(5 citation statements)

References 23 publications

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“…Due to theoretical advantages in studying physiological phenomena in single cells (especially the ability to control the extracellular environment rapidly and predictably and a very small extracellular space so that small fluxes of ions critical for secretion can be detected), investigators have tried to use dissociated pancreatic acinar cells obtained by combined procedures of digestion of tissue by enzymes, mechanical disruption and Ca2+ chelation with EGTA or EDTA (Amsterdam & Jamieson, 1974a;Gardner, Conlon, Klaeveman, Adams & Ondetti, 1975;Williams, Cary & Moffat, 1976;Kondo & Schulz, 1976;Kempen, DePont & Bonting, 1977;Renckens, Schrijen, Swarts, DePont & Bonting, 1978;Case & Clausen (see Case, 1978); Singh, 1978Singh, , 1980b. However, in practice, it has been observed that dissociated cells respond poorly to physiological secretagogues (Kondo & Schulz, 1976), possibly due to damage of cell surface receptors (Case, 1978) and need about a tenfold greater concentration of agonists than intact tissue to elicit enzyme secretion (Amsterdam & Jamieson, 1974b;Williams et at.…”

Section: Discussionmentioning

confidence: 99%

Amylase release from dissociated mouse pancreatic acinar cells stimulated by glucagon: effect of membrane stabilizers.

Singh¹

1980

The Journal of Physiology

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SUMMARY1. The effect of membrane stabilizers and cytochalasin-B on amylase secretion, basal and induced by ionophore A23187, CCK-PZ, bethanechol and glucagon, was studied in dissociated mouse pancreatic acinar cells.2. Cytochalasin-B did not affect basal or secretagogue-stimulated amylase secretion.3. Membrane stabilizers [thymol (10-7-104 M), chlorpromazine (I0-7-1 04 M) and propranolol (10-7-10-5 M) did not alter basal release of amylase. At higher concentrations of thymol (10-3 M), chlorpromazine (10-3 M) and propranolol (104M), dissociated acinar cells were lysed as indicated by an increase in release of lactic dehydrogenase (LDH).4. Ionophore A23187, CCK-PZ (maximal effective concentrations, 0*01 u. ml.-'), bethanechol (maximal effective concentrations, 10-4 M) and glucagon increased amylase secretion in a dose-dependent fashion. Concentrations of CCK-PZ and bethanechol beyond optimal levels decreased amylase secretion. Concentrations of ionophore A23187 and glucagon when tested beyond 10-6 M and 104 M respectively increased the release of LDH. In concentrations that were non-toxic, membrane stabilizers blocked the stimulating effect of chlolecystokinin-pancreozymin and bethanechol on amylase secretion but did not alter the response to A23187 and glucagon.5. Unlike bethanechol, glucagon neither increased the uptake of 45Ca nor did it alter the release of 45Ca from cells previously loaded with 45CaCl2.6. These data provide evidence that stimulus-secretion coupling in dissociated pancreatic acinar cells is basically similar to cells in situ. The effect of glucagon is consistent with the model in which hormone-dependent mobilization of Ca2+ from intra-or extracellular sources is bypassed leading to digestive enzyme secretion.

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Section: Discussionmentioning

confidence: 99%

Amylase release from dissociated mouse pancreatic acinar cells stimulated by glucagon: effect of membrane stabilizers.

Singh¹

1980

The Journal of Physiology

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“…Evidence suggests that the intracellular free calcium concentration is an important factor in the sequence of events leading to enzyme secretion in pancreatic acinar cells [4,14,15,19,21,24,28,29,43,47,49,55]. At least three structures are considered to influence the cytosolic calcium concentration: plasma membrane [30,43,55], mitochondria [5,6,10,12] and one or more not yet clearly identified nonmitochondrial structures [12,33,44,46].…”

Section: Introductionmentioning

confidence: 98%

Characterization of calcium uptake into rough endoplamic reticulum of rat pancreas

et al. 1984

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ATP-dependent Ca2+ uptake into isolated pancreatic acinar cells with permeabilized plasma membranes, as well as into isolated endoplasmic reticulum prepared from these cells, was measured using a Ca2+ -specific electrode and 45Ca2+. Endoplasmic reticulum was purified on an isopycnic Percoll gradient and characterized by marker enzyme distribution. When compared to the total homogenate, the typical marker for the rough endoplasmic reticulum RNA was enriched threefold and the typical marker for the plasma membrane Na+,K+(Mg2+)ATPase was decreased 20-fold. When different fractions of the Percoll gradient were compared, 45Ca2+ uptake correlated with the RNA content and not with the Na+,K+(Mg2+)ATPase activity. The characteristics of nonmitochondrial Ca2+ uptake into leaky isolated cells and 45Ca2+ uptake into isolated endoplasmic reticulum were very similar: Calcium uptake was maximal at 0.3 and 0.2 mmol/liter free Mg2+, at 1 and 1 mmol/liter ATP, at pH 6.0 and 6.5, and free Ca2+ concentration of 2 and 2 mumol/liter, respectively. Calcium uptake decreased at higher free Ca2+ concentration. 45Ca2+ uptake was dependent on monovalent cations (Rb+ greater than K+ greater than Na+ greater than Li+ greater than choline+) and different anions (Cl- greater than Br- greater than SO4(2-) greater than NO3- greater than I- greater than cyclamate- greater than SCN-) in both preparations. Twenty mmol/liter oxalate enhanced 45Ca2+ uptake in permeabilized cells 10-fold and in vesicles of endoplasmic reticulum, fivefold. Calcium oxalate precipitates in the endoplasmic reticulum of both preparations could be demonstrated by electron microscopy. The nonmitochondrial Ca2+ pool in permeabilized cells characterized in this study has been previously shown to regulate the cytosolic free Ca2+ concentration to 0.4 mumol/liter. Our results provide firm evidence that the endoplasmic reticulum plays an important role in the regulation of the cytosolic free Ca2+ concentration in pancreatic acinar cells.

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“…Experiments in which isolated acinar cells had been preincubated with 45Ca2 § until steady state had been reached have shown biphasic ~SCa 2 + movements following stimulation with secretagogues of en-zyme secretion. An initial phase of 45Ca2+ release is followed by ~5Ca2 + reuptake that can exceed the control value [16,26,55,60,62]. Addition of an antagonist such as atropine following carbachol caused a further rapid 4SCa2 § uptake with subsequent decline back to the control.…”

Section: Introductionmentioning

confidence: 99%

Calcium uptake into acini from rat pancreas: Evidence for intracellular ATP-dependent calcium sequestration

et al. 1982

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Intracellular ATP-dependent Ca2+-sequestration mechanisms were studied in isolated dispersed rat pancreatic acini following treatment with saponin or digitonin to disrupt their plasma membranes. In the presence of 45Ca2+ concentrations less than 10(-6) mol/liter, addition of 5 mmol/liter ATP caused a rapid increase in 45Ca2+ uptake exceeding the control by fivefold. ADP mimicked the ATP effect by 50 to 60%, whereas other nucleotides such as AMP-PNP, AMP-PCP, CTP, UTP, ITP, GTP, cAMP and cGMP did not. Maximal ATP-promoted Ca2+ uptake was obtained at 10(-5) mol/liter Ca2+. Inhibition of Ca2+ uptake by mitochondrial inhibitors was dependent on the Ca2+ concentration, indicating the presence of different Ca2+ storage systems. Whereas the apparent half-saturation constant found for mitochondrial Ca2+ uptake was approximately 4.5 X 10(-7) mol/liter, in the presence of antimycin and oligomycin (nonmitochondrial uptake) it was approximately 1.4 X 10(-8) mol/liter. In the absence of Mg2+ both ATP- and ADP-promoted Ca2+ uptake was nearly abolished. The Ca2+ ionophore and mersalyl blocked Ca2+ uptake, Electron microscopy showed electron-dense precipitates in the rough endoplasmic reticulum of saponin-treated cells in the presence of Ca2+, oxalate and ATP, which were absent in intact cells and in saponin-cells without ATP or pretreated with A23187. The data suggest the presence of mitochondrial and nonmitochondrial ATP-dependent C2+ storage systems in pancreatic acini. The latter is likely to be located in the rough endoplasmic reticulum.

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Role of calcium in exocrine pancreatic secretion. IV. Calcium movements in isolated acinar cells of rabbit pancreas

Cited by 19 publications

References 23 publications

Amylase release from dissociated mouse pancreatic acinar cells stimulated by glucagon: effect of membrane stabilizers.

Amylase release from dissociated mouse pancreatic acinar cells stimulated by glucagon: effect of membrane stabilizers.

Characterization of calcium uptake into rough endoplamic reticulum of rat pancreas

Calcium uptake into acini from rat pancreas: Evidence for intracellular ATP-dependent calcium sequestration

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