scholarly journals Ins(1,3,4,5)P4 is effective in mobilizing Ca2+ in mouse exocrine pancreatic acinar cells if phospholipase A2 is inhibited

1996 ◽  
Vol 319 (3) ◽  
pp. 913-918 ◽  
Author(s):  
Sarah-Jayne ROWLES ◽  
David V GALLACHER
Keyword(s):  
Phospholipase A2 ◽  
Surface Membrane ◽  
Acinar Cells ◽  
Receptor Activation ◽  
Inhibitory Effect ◽  
Membrane Currents ◽  
Pancreatic Acinar Cells ◽  
Inositol Polyphosphate ◽  
Internal Perfusion ◽  
Inositol Polyphosphates

In enzymically isolated mouse pancreatic acinar cells, under conditions of whole-cell patch-clamp current recording, the effect of phospholipase C-coupled agonists can be mimicked by internal perfusion of the intracellular second messenger Ins(1,4,5)P3 (10 µM) or its analogue Ins(2,4,5)P3 (10 µM). The inositol trisphosphates mimic receptor activation by releasing Ca2+ from intracellular stores and by promoting Ca2+ influx across the surface membrane. This Ca2+-mobilizing role of inositol polyphosphates seems to be confined to the inositol trisphosphates because internal perfusion of Ins(1,3,4,5)P4 (10 µM) is not associated with any Ca2+-dependent current activation. In this study we investigate the effects of 4-bromophenacyl bromide (4BPB), a putative inhibitor of phospholipase A2 and arachadonic acid production, on inositol polyphosphate-induced Ca2+ signalling. At 10 µM, 4BPB has no effect on unstimulated Ca2+-dependent membrane currents. However, if 4BPB is applied to cells internally perfused with 10 µM Ins(1,4,5)P3 or Ins(2,4,5)P3 then the current responses are rapidly potentiated. In cells internally perfused with 10 µM Ins(1,3,4,5)P4, which has itself no effect on membrane currents, application of 4BPB resulted in the activation of Ca2+-dependent currents, seen either as repetitive spikes of current or as sustained current activations. The application of arachidonic acid blocks the current responses evoked by the inositol trisphosphates and by Ins(1,3,4,5)P4/4BPB. These results suggest that in enzymically isolated pancreatic acinar cells phospholipase A2 activity is exerting an inhibitory effect on inositol polyphosphate-mediated Ca2+ mobilization. 4BPB removes this inhibition and potentiates the responses to internally perfused inositol trisphosphates and, importantly, makes 10 µM Ins(1,3,4,5)P4 as effective as 10 µM Ins(1,4,5)P3 in mobilizing intracellular Ca2+ and in promoting Ca2+ influx.

High-affinity CCK receptors are coupled to phospholipase A2 pathways to mediate pancreatic amylase secretion

1995 ◽  
Vol 269 (3) ◽  
pp. G435-G444 ◽  
Author(s):  
Y. Tsunoda ◽  
C. Owyang
Keyword(s):  
Phospholipase A2 ◽  
Acinar Cells ◽  
Receptor Activation ◽  
Pancreatic Acinar Cells ◽  
Rabbit Serum ◽  
Amylase Secretion ◽  
Pancreatic Acini ◽  
Cck Receptors ◽  
Permeabilized Cells ◽  
High Affinity

It is well recognized that JMV-180, a cholecystokinin (CCK) analogue, acts as an agonist on the high-affinity CCK receptor in pancreatic acinar cells. It caused Ca2+ oscillations and amylase secretion in a manner independent of the phospholipase C-inositol 1,4,5-trisphosphate (IP3) pathway. We investigated the mechanism by which the high-affinity CCK receptor utilizes IP3-independent Ca2+ signal transduction to mediate amylase secretion. JMV-180 (1-1,000 nM)-stimulated Ca2+ oscillations and amylase secretion were significantly inhibited by the phospholipase A2 (PLA2) inhibitor, ONO-RS-082 (10 microM). Using streptolysin O-permeabilized cells, we showed that a porcine pancreatic anti-PLA2 antibody from rabbit serum (250 ng/ml) inhibited JMV-180-stimulated amylase secretion. In contrast to CCK octapeptide, JMV-180 (1 nM-10 microM) had no effect on intracellular IP3 levels. These concentrations of JMV-180 did, however, increase intracellular levels of arachidonic acid (AA) metabolite by 2.5-fold in a biphasic manner. Application of exogenous AA (10 microM) released 60% of ATP-incorporated 45Ca2+ from permeabilized pancreatic acini within 3 min in a transient manner. We also showed that active phorbol ester (100 nM) inhibited Ca2+ oscillations and amylase secretion stimulated by JMV-180 (10 nM) or CCK-OPE (100 nM). Application of Mn2+ (2 mM) to superfused acini resulted in a rapid quench of fura 2 fluorescence during 10 nM JMV-180 stimulation, suggesting an involvement of extracellular Ca2+ influx. However, the major source of Ca2+ utilized for oscillations during high-affinity CCK receptor activation was intracellular. In conclusion, we have demonstrated that the high-affinity CCK receptors are coupled to PLA2 pathways to produce AA, which mediates cytosolic Ca2+ oscillation and monophasic amylase secretion, in rat pancreatic acinar cells.

scholarly journals The Ecto-enzyme CD38 Is a Nicotinic Acid Adenine Dinucleotide Phosphate (NAADP) Synthase That Couples Receptor Activation to Ca2+Mobilization from Lysosomes in Pancreatic Acinar Cells

2010 ◽  
Vol 285 (49) ◽  
pp. 38251-38259 ◽  
Author(s):  
François Cosker ◽  
Nathalie Cheviron ◽  
Michiko Yamasaki ◽  
Alexis Menteyne ◽  
Frances E. Lund ◽  
...  
Keyword(s):  
Nicotinic Acid ◽  
Acinar Cells ◽  
Receptor Activation ◽  
Pancreatic Acinar Cells

scholarly journals Inhibitory effect of high leucine concentration on α-amylase secretion by pancreatic acinar cells: possible key factor of proteasome

2018 ◽  
Vol 38 (6) ◽  
Author(s):  
Long Guo ◽  
Baolong Liu ◽  
Chen Zheng ◽  
Hanxun Bai ◽  
Hao Ren ◽  
...  
Keyword(s):  
Amylase Activity ◽  
Acinar Cells ◽  
Inhibitory Effect ◽  
Proteasome Activity ◽  
Pancreatic Acinar Cells ◽  
Amylase Secretion ◽  
High Concentration ◽  
Amylase Release ◽  
Cholecystokinin Receptor ◽  
Key Factor

The present study aimed to investigate whether leucine affects the pancreatic exocrine by controlling the antisecretory factor (AF) and cholecystokinin receptor (CCKR) expression as well as the proteasome activity in pancreatic acinar cells of dairy calves. The pancreatic acinar cells were isolated from newborn Holstein bull calves and cultured using the Dulbecco’s modified Eagle’s medium/nutrient mixture F12 Ham’s liquid (DMEM/F12). There were six treatments of leucine dosage including 0 (control), 0.23, 0.45, 1.35, 4.05, and 12.15 mM, respectively. After culture for 3 h, the samples were collected for subsequent analysis. As the leucine concentration increased from 0 to 1.35 mM, the α-amylase activity in media decreased significantly (P<0.05), while further increase in leucine concentration did not show any decrease in α-amylase activity. Addition of leucine inhibited (P<0.05) the expression of AF and CCKR, and decreased the activity of proteasome (P<0.05) by 76%, 63%, 24%, 7%, and 9%, respectively. Correlation analysis results showed α-amylase secretion was negatively correlated with leucine concentration (P<0.01), and positively correlated with proteasome activity (P<0.01) and the expression of CCK1R (P<0.01) and AF (P<0.05). The biggest regression coefficient was showed between α-amylase activity and proteasome (0.7699, P<0.001). After inhibition of proteasome by MG-132, low dosage leucine decreased (P<0.05) the activity of proteasome and α-amylase, as well as the expression of CCK1R. In conclusion, we demonstrated that the high-concentration leucine induced decrease in α-amylase release was mainly by decreasing proteasome activity.

scholarly journals Morphometric Measurements to Quantify the Cerulein Induced Hyperstimulatory Pancreatitis of Rats under the Protective Effect of Lectins

1998 ◽  
Vol 17 (4) ◽  
pp. 219-230 ◽  
Author(s):  
Ludwig Jonas ◽  
Ulrike Mikkat ◽  
Anke Witte ◽  
Uta Beckmann ◽  
Katrin Dölker ◽  
...  
Keyword(s):  
Protective Effect ◽  
Amylase Activity ◽  
Acinar Cells ◽  
Inhibitory Effect ◽  
Pancreatic Acinar Cells ◽  
Amylase Secretion ◽  
Ulex Europaeus ◽  
Serum Amylase Activity

In preceding papers we demonstrated an inhibitory effect of wheat germ agglutinin (WGA) and Ulex europaeus agglutinin (UEA) on the cholecystokinin (CCK) binding to the CCK receptor of rat pancreatic cells and also on the CCK induced Ca2+release and α-amylase secretionin vitroas well as on pancreatic secretion of intact ratsin vivo. In the present study we show the same inhibitory effect of both lectins on the cerulein pancreatitis of rats. This acute pancreatitis was induced by supramaximal injections (5 µg/kg/h iv or 10 µg/kg/h ip) of the CCK analogue cerulein in rats every hour. To monitor the degree of pancreatitis, we measured the number and diameter of injury vacuoles in the pancreatic acinar cells as one of the most important signs of this type of pancreatitis by light microscopic morphometry with two different systems on paraffin sections. Furthermore, the serum α-amylase activity was measured biochemically. We found a correlation between the diameter of vacuoles inside the acinar cells and the serum enzyme activity up to 24 h. The simultaneous ip administration of cerulein and WGA or UEA in a dosage of 125 µg/kg/h for 8 h led to a reduction of vacuolar diameter from 13.1 ± 2.0 µm (cerulein) to 7.5 ± 1.1 µm (cerulein + WGA) or 7.2 ± 1.3 µm (cerulein + UEA). The serum amylase activity was reduced from 63.7 ± 15.8 mmol/l \times min (cerulein) to 37.7 ± 11.8 (cerulein + WGA) or 39.4; +52.9; -31.1 (cerulein + UEA-I). Both parameters allow the grading this special type of pancreatitis to demonstrate the protective effect of the lectins.

scholarly journals Ca2+-sensitivity of inositol 1,4,5-trisphosphate-mediated Ca2+ release in permeabilized pancreatic acinar cells

1990 ◽  
Vol 265 (3) ◽  
pp. 681-687 ◽  
Author(s):  
P H G M Willems ◽  
M D De Jong ◽  
J J H H M De Pont ◽  
C H Van Os
Keyword(s):  
Acinar Cells ◽  
Inhibitory Effect ◽  
Feedback Mechanism ◽  
Pancreatic Acinar Cells ◽  
Release Mechanism ◽  
Concomitant Increase ◽  
Permeabilized Cells ◽  
Negative Feedback Mechanism ◽  
Inositol 1,4,5 Trisphosphate ◽  
Energy Dependent

Hormonal and phorbol ester pretreatment of pancreatic acinar cells markedly decreases the Ins(1,4,5)P3-induced release of actively stored Ca2+ [Willems, Van Den Broek, Van Os & De Pont (1989) J. Biol. Chem. 264, 9762-9767]. Inhibition occurred at an ambient free Ca2+ concentration of 0.1 microM, suggesting a receptor-mediated increase in Ca2(+)-sensitivity of the Ins(1,4,5)P3-operated Ca2+ channel. To test this hypothesis, the Ca2(+)-dependence of Ins(1,4,5)P3-induced Ca2+ release was investigated. In the presence of 0.2 microM free Ca2+, permeabilized cells accumulated 0.9 nmol of Ca2+/mg of acinar protein in an energy-dependent pool. Uptake into this pool increased 2.2- and 3.3-fold with 1.0 and 2.0 microM free Ca2+ respectively. At 0.2, 1.0 and 2.0 microM free Ca2+, Ins(1,4,5)P3 maximally released 0.53 (56%), 0.90 (44%) and 0.62 (20%) nmol of Ca2+/mg of acinar protein respectively. Corresponding half-maximal stimulatory Ins(1,4,5)P3 concentrations were calculated to be 0.5, 0.6 and 1.4 microM, suggesting that the affinity of Ins(1,4,5)P3 for its receptor decreases beyond 1.0 microM free Ca2+. The possibility that an inhibitory effect of sub-micromolar Ca2+ is being masked by the concomitant increase in size of the releasable store is excluded, since Ca2+ release from cells loaded in the presence of 0.1 or 0.2 microM free Ca2+ and stimulated at higher ambient free Ca2+ was not inhibited below 1.0 microM free Ca2+. At 2.0 and 10.0 microM free Ca2+, Ca2+, Ca2+ release was inhibited by approx. 30% and 75% respectively. The results presented show that hormonal pretreatment does not lead to an increase in Ca2(+)-sensitivity of the release mechanism. Such an increase in Ca2(+)-sensitivity to sub-micromolar Ca2+ is required to explain sub-micromolar oscillatory changes in cytosolic free Ca2+ by a Ca2(+)-dependent negative-feedback mechanism.

Effects of Phospholipase A2 Inhibitors on Ca2+ Oscillations in Pancreatic Acinar Cells

Pancreas ◽  
2000 ◽  
Vol 20 (1) ◽  
pp. 77-83 ◽  
Author(s):  
Nobumasa Mizuno ◽  
Satoru Naruse ◽  
Motoji Kitagawa ◽  
Hiroshi Ishiguro ◽  
Tetsuo Hayakawa
Keyword(s):  
Phospholipase A2 ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Phospholipase A2 Inhibitors

scholarly journals Role of cyclic GMP in the control of capacitative Ca2+ entry in rat pancreatic acinar cells

1995 ◽  
Vol 311 (2) ◽  
pp. 649-656 ◽  
Author(s):  
P Gilon ◽  
J F Obie ◽  
X Bian ◽  
G S J Bird ◽  
J W Putney
Keyword(s):  
Sodium Nitroprusside ◽  
Cyclic Gmp ◽  
Acinar Cells ◽  
Inhibitory Effect ◽  
Pancreatic Acinar Cells ◽  
Inhibitory Effects ◽  
Intracellular Cgmp ◽  
Agonist Stimulation ◽  
Ly 83583

We have investigated the possible roles of cyclic GMP (cGMP) in initiating or regulating capacitiative Ca2+ entry in rat pancreatic acinar cells. In medium containing 1.8 mM external Ca2+, thapsigargin activated Ca2+ entry and slightly but significantly increased intracellular cGMP concentration. This rise in cGMP levels was prevented by pretreating the cells with the guanylate cyclase inhibitor, LY-83583, or by omitting Ca2+ during stimulation by thapsigargin or methacholine. LY-83583 and NG-nitro-L-arginine (L-NA, an inhibitor of NO synthase) both had a small inhibitory effect on Ca2+ entry when they were added after thapsigargin in Ca2(+)-containing medium, and they reduced by 32 and 48% respectively the thapsigargin-induced capacitative Ca2+ entry when added to the cells during a 20 min preincubation period. However, neither dibutyryl cGMP (Bt2cGMP) nor sodium nitroprusside, an NO mimic, affected either basal intracellular Ca2+ concentration [Ca2+]i or thapsigargin-induced capacitative Ca2+ entry. Further, the inhibitory effects observed after preincubation with LY-83583 or L-NA could not be prevented by preincubation with Bt2cGMP, nor could they be reversed by adding Bt2cGMP, 8-bromo-cGMP or sodium nitroprusside acutely after activation of capacitative Ca2+ entry by thapsigargin. Finally, pretreatment of cells with LY-83583 or L-NA did not affect Ca2+ signalling in response to 1 microM methacholine, including the pattern of [Ca2+]i oscillations. In conclusion, in pancreatic acinar cells, the rise in cellular cGMP levels appears to depend on, rather than cause, the increase in [Ca2+]i with agonist stimulation.

Ethanol differentially regulates NF-κB activation in pancreatic acinar cells through calcium and protein kinase C pathways

2004 ◽  
Vol 286 (2) ◽  
pp. G204-G213 ◽  
Author(s):  
Anna S. Gukovskaya ◽  
Saeed Hosseini ◽  
Akihiko Satoh ◽  
Jason H. Cheng ◽  
Kyung J. Nam ◽  
...  
Keyword(s):  
Acinar Cells ◽  
Inhibitory Effect ◽  
Pancreatic Acinar Cells ◽  
Alcoholic Pancreatitis ◽  
Pancreatic Acini ◽  
Intracellular Ca ◽  
Ethanol Feeding ◽  
Ethanol Ethanol

Mechanisms of alcoholic pancreatitis remain unknown. Previously, we showed that ethanol feeding sensitizes rats to pancreatitis caused by CCK-8, at least in part, by augmenting activation of the proinflammatory transcription factor NF-κB. To elucidate the mechanism of sensitization, here we investigate the effect of ethanol on Ca2+- and PKC-mediated pathways of CCK-induced NF-κB activation using an in vitro system of rat pancreatic acini incubated with ethanol. Ethanol augmented CCK-8-induced activation of NF-κB, similar to our in vivo findings with ethanol-fed rats. In contrast, ethanol prevented NF-κB activation caused by thapsigargin, an agent that mobilizes intracellular Ca2+ bypassing the receptor. Pharmacological analysis showed that NF-κB activation by thapsigargin but not by CCK-8 is mediated through the calcineurin pathway and that the inhibitory effect of ethanol on the thapsigargin-induced NF-κB activation could be through inhibiting this pathway. Ethanol augmented NF-κB activation induced by the phorbol ester PMA, a direct activator of PKC. Inhibitory analysis demonstrated that Ca2+-independent (novel and/or atypical) PKC isoforms are involved in NF-κB activation induced by both CCK-8 and PMA in cells treated and not treated with ethanol. The results indicate that ethanol differentially affects the Ca2+/calcineurin- and PKC-mediated pathways of NF-κB activation in pancreatic acinar cells. These effects may play a role in the ability of ethanol to sensitize pancreas to the inflammatory response and pancreatitis.

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