Swelling-induced changes in cytosolic [Ca2+] in insulin-secreting cells: a role in regulatory volume decrease?

Sheader, Elizabeth; Brown, Peter de Nully; Best, Leonard

doi:10.1016/s0303-7207(01)00509-3

Cited by 28 publications

(35 citation statements)

References 25 publications

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“…1C, D and 3B). This biphasic response is in line with previous work on isolated β-cells [7] and RINm5F insulinoma cells [37]. Under RV electrical activity ceased and the MP was reversibly repolarized.…”

Section: Resultssupporting

confidence: 91%

Resveratrol Inhibits Electrical Activity and Insulin Release from Insulinoma Cells by Block of Voltage-Gated Ca2+ Channels and Swelling-Dependent Cl- Currents

Jakab

Lach²,

Bačová³

et al. 2008

Cell Physiol Biochem

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The phytostilbene resveratrol (RV) improves the metabolic state in animal models by increasing the insulin responsiveness of tissues and there is evidence that RV affects insulin secretion from native β-cells and insulinoma cells. In whole cell patch clamp experiments on clonal rat INS-1E cells we used high extracellular glucose (20 mM), extracellular hypotonicity (30%) or tolbutamide (100 μM) to elicit membrane depolarizations and electrical activity. Application of RV (50 μM) repolarized the cells, terminated electrical activity and prevented the hypotonicity-induced depolarization. These effects were fully reversible and intermittent application of RV restored tolbutamide-induced electrical activity after desensitization. Glucose-induced depolarization was counteracted by RV in presence of iberiotoxin (50 nM), showing that the RV effect does not depend on BK_Ca channel activation. RV dose-dependently inhibited K_ATP currents, L- and T-type Ca²⁺ currents and swelling-dependent Cl^- currents evoked by either hypotonicity or high extracellular glucose - ion conductances crucially involved in regulating the electrical activity of insulin secreting cells. We further show that RV blunts glucose-induced, but not basal insulin release. Our results indicate that RV counteracts/prevents stimulus-induced cell membrane depolarization and electrical activity by blocking voltage-gated Ca²⁺- and swelling-dependent Cl^- currents despite the inhibition of K_ATP currents.

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Section: Resultssupporting

confidence: 91%

Resveratrol Inhibits Electrical Activity and Insulin Release from Insulinoma Cells by Block of Voltage-Gated Ca2+ Channels and Swelling-Dependent Cl- Currents

Jakab

Lach²,

Bačová³

et al. 2008

Cell Physiol Biochem

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“…In this case, Ca 2+ release from the store occurred upon stretching the store membrane, which was evoked by osmotic swelling of cytoplasm or mechanical agitation of an isolated cytoplasmic drop. A similar phenomenon was observed in insulin-secreting cells: hypotonic swelling of RINm5F insulinoma cells caused a marked increase in cytoplasmic [Ca 2+ ] (Sheader et al 2001). Mechanosensitive Ca 2+ channels have been reported in epithelial cells isolated from the endolymphatic sac of guinea pigs (Miyashita et al 2001), human smooth muscle (Holm et al 2001) and yeast (Kanzaki et al 1999, Maruoka et al 2002.…”

Section: +supporting

confidence: 67%

Possible Involvement of Mechanosensitive Ca2+ Channels of Plasma Membrane in Mechanoperception in Chara

Kaneko

Saito

Shimmen

et al. 2005

Plant and Cell Physiology

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;When an internodal cell of Chara corallina was stimulated with a mechanical pulse of various amplitudes lasting for 0.1 s (mechanical stimulus), the cell generated a receptor potential, which was highly dependent not only on the strength of the stimulus but also on the extracellular Cl -concentration. Extracellular Ca 2+ was indispensable for generating receptor potential, since removal of Ca 2+ reversibly inhibited generation of the receptor potential. The cytoplasmic Ca 2+ level transiently rose upon mechanical stimulation. The stronger the mechanical stimulus, the larger was the increase in the cytoplasmic level of Ca 2+ . It is proposed that the first step of receptor potential is an activation of mechanosensitive Ca 2+ channels at the plasma membrane.

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“…Because high concentrations of glucose have been shown to increase ␤-cell volume (18,20), cell swelling may be involved in the glucoseinduced insulin secretion. Several studies have suggested that cell swelling releases insulin by activating volume-sensitive Cl Ϫ channels, thus depolarizing the ␤-cell membrane and increasing the cytosolic Ca 2ϩ concentration ([Ca 2ϩ ] c ) via the activation of voltage-dependent Ca 2ϩ channels (VDCC) (2,3,6,13,21). However, several reports have argued against this proposition by showing that hypotonically induced insulin secretion persists even in the presence of Cl Ϫ channel blockers such as niflumic acid and DIDS (12,22).…”

mentioning

confidence: 99%

Involvement of stretch-activated cation channels in hypotonically induced insulin secretion in rat pancreatic β-cells

Takii

Ishikawa²,

Tsuda³

et al. 2006

American Journal of Physiology-Cell Physiology

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In isolated rat pancreatic beta-cells, hypotonic stimulation elicited an increase in cytosolic Ca(2+) concentration ([Ca(2+)](c)) at 2.8 mM glucose. The hypotonically induced [Ca(2+)](c) elevation was significantly suppressed by nicardipine, a voltage-dependent Ca(2+) channel blocker, and by Gd(3+), amiloride, 2-aminoethoxydiphenylborate, and ruthenium red, all cation channel blockers. In contrast, the [Ca(2+)](c) elevation was not inhibited by suramin, a P(2) purinoceptor antagonist. Whole cell patch-clamp analyses showed that hypotonic stimulation induced membrane depolarization of beta-cells and produced outwardly rectifying cation currents; Gd(3+) inhibited both responses. Hypotonic stimulation also increased insulin secretion from isolated rat islets, and Gd(3+) significantly suppressed this secretion. Together, these results suggest that osmotic cell swelling activates cation channels in rat pancreatic beta-cells, thereby causing membrane depolarization and subsequent activation of voltage-dependent Ca(2+) channels and thus elevating insulin secretion.

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Swelling-induced changes in cytosolic [Ca2+] in insulin-secreting cells: a role in regulatory volume decrease?

Cited by 28 publications

References 25 publications

Resveratrol Inhibits Electrical Activity and Insulin Release from Insulinoma Cells by Block of Voltage-Gated Ca<sup>2+</sup> Channels and Swelling-Dependent Cl<sup>-</sup> Currents

Resveratrol Inhibits Electrical Activity and Insulin Release from Insulinoma Cells by Block of Voltage-Gated Ca<sup>2+</sup> Channels and Swelling-Dependent Cl<sup>-</sup> Currents

Possible Involvement of Mechanosensitive Ca2+ Channels of Plasma Membrane in Mechanoperception in Chara

Involvement of stretch-activated cation channels in hypotonically induced insulin secretion in rat pancreatic β-cells

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