Involvement of stretch-activated cation channels in hypotonically induced insulin secretion in rat pancreatic [beta]-cells

In isolated rat pancreatic ...-cells, hypotonic stimulation elicited an increase in cytosolic Ca2+ concentration (...) at 2.8 mM glucose. The hypotonically induced ... elevation was significantly suppressed by nicardipine, a voltage-dependent Ca2+ channel blocker, and by Gd... amiloride, 2-aminoetho...

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Bibliographic Details
Published in:American Journal of Physiology: Cell Physiology 2006-12, Vol.291 (6), p.C1405
Main Authors: Takii, Miki, Ishikawa, Tomohisa, Tsuda, Hidetaka, Kanatani, Kazumitsu
Format: Article
Language:English
Subjects:
Calcium
Cellular biology
Glucose
Insulin
Ions
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Summary:In isolated rat pancreatic ...-cells, hypotonic stimulation elicited an increase in cytosolic Ca2+ concentration (...) at 2.8 mM glucose. The hypotonically induced ... elevation was significantly suppressed by nicardipine, a voltage-dependent Ca2+ channel blocker, and by Gd... amiloride, 2-aminoethoxydiphenylborate, and ruthenium red, all cation channel blockers. In contrast, the ... elevation was not inhibited by suramin, a P... purinoceptor antagonist. Whole cell patch-clamp analyses showed that hypotonic stimulation induced membrane depolarization of ...-cells and produced outwardly rectifying cation currents; Gd... inhibited both responses. Hypotonic stimulation also increased insulin secretion from isolated rat islets, and Gd... significantly suppressed this secretion. Together, these results suggest that osmotic cell swelling activates cation channels in rat pancreatic ...-cells, thereby causing membrane depolarization and subsequent activation of voltage-dependent Ca2+ channels and thus elevating insulin secretion. (ProQuest Information and Learning: ... denotes formulae omitted.)
ISSN:0363-6143
1522-1563