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Decrease of acidity inside zymogen granules inhibits acetylcholine- or inositol trisphosphate-evoked cytosolic Ca2+ spiking in pancreatic acinar cells.

A V Titievsky·T Takeo·A V Tepikin·O H Petersen
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Abstract

In isolated pancreatic acinar cells application of the proton-potassium ionophore nigericin or the proton-sodium ionophore monensin led to a reduction of acidity inside the zymogen granules which could be visualized in an imaging system by a rapid reduction in the intragranular quinacrine fluorescence. Cytosolic Ca2+ spikes in response to acetylcholine stimulation or intracellular inositol trisphosphate application were assessed by recording Ca2+ -sensitive ionic currents in the patch clamp whole-cell recording configuration. Both nigericin and monensin evoked marked reductions in frequency and amplitude of spikes and in many experiments abolished spiking altogether. The Ca2+ -sensitive membrane currents could still be activated after nigericin or monensin treatment since subsequent application of the Ca2+ ionophore ionomycin evoked a large current response. The decrease in intragranular acidity would appear to inhibit intracellular Ca2+ release perhaps due to a reduction in the free intragranular Ca2+ concentration.

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AcetylcholineAnimalsCalciumCytoplasmic GranulesCytosolEnzyme PrecursorsHydrogen-Ion ConcentrationInositol 1,4,5-TrisphosphateMonensinNigericinPancreasQuinacrineValinomycinJournal ArticleResearch Support, Non-U.S. Gov't

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A V Titievsky, T Takeo, A V Tepikin, O H Petersen. 1996. Decrease of acidity inside zymogen granules inhibits acetylcholine- or inositol trisphosphate-evoked cytosolic Ca2+ spiking in pancreatic acinar cells.. https://doi.org/10.1007/s004240050218

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