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- Title
Evidence for Presence and Functional Effects of Kv1.1 Channels in β-Cells: General Survey and Results from mceph/mceph Mice.
- Authors
Zuheng Ma; Lavebratt, Catharina; Almgren, Malin; Portwood, Neil; Forsberg, Lars E.; Bränström, Robert; Berglund, Erik; Falkmer, Sture; Sundler, Frank; Wierup, Nils; Björklund, Anneli
- Abstract
Background: Voltage-dependent K+ channels (Kv) mediate repolarisation of b-cell action potentials, and thereby abrogate insulin secretion. The role of the Kv1.1 K+ channel in this process is however unclear. We tested for presence of Kv1.1 in different species and tested for a functional role of Kv1.1 by assessing pancreatic islet function in BALB/cByJ (wild-type) and megencephaly (mceph/mceph) mice, the latter having a deletion in the Kv1.1 gene. Methodology/Principal Findings: Kv1.1 expression was detected in islets from wild-type mice, SD rats and humans, and expression of truncated Kv1.1 was detected in mceph/mceph islets. Full-length Kv1.1 protein was present in islets from wildtype mice, but, as expected, not in those from mceph/mceph mice. Kv1.1 expression was localized to the β-cell population and also to α- and δ-cells, with evidence of over-expression of truncated Kv1.1 in mceph/mceph islets. Blood glucose, insulin content, and islet morphology were normal in mceph/mceph mice, but glucose-induced insulin release from batchincubated islets was (moderately) higher than that from wild-type islets. Reciprocal blocking of Kv1.1 by dendrotoxin-K increased insulin secretion from wild-type but not mceph/mceph islets. Glucose-induced action potential duration, as well as firing frequency, was increased in mceph/mceph mouse β-cells. This duration effect on action potential in β-cells from mceph/mceph mice was mimicked by dendrotoxin-K in β-cells from wild-type mice. Observations concerning the effects of both the mceph mutation, and of dendrotoxin-K, on glucose-induced insulin release were confirmed in pancreatic islets from Kv1.1 null mice. Conclusion/Significance: Kv1.1 channels are expressed in the b-cells of several species, and these channels can influence glucose-stimulated insulin release.
- Subjects
ELECTRIC potential; INSULIN; LABORATORY mice; GENE expression; ISLANDS of Langerhans; GLUCOSE
- Publication
PLoS ONE, 2011, Vol 6, Issue 4, p1
- ISSN
1932-6203
- Publication type
Article
- DOI
10.1371/journal.pone.0018213