Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Oscillatory Ca2+ signaling in glucose-stimulated murine pancreatic β-cells: Modulation by amino acids, glucagon, caffeine and ryanodine
Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Medical Cell Biology.
2001 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Oscillations in cytoplasmic Ca2+ concentration ([Ca2+]i) is the key signal in glucose-stimulated β-cells governing pulsatile insulin release. The glucose response of mouse β-cells is often manifested as slow oscillations and rapid transients of [Ca2+] i. In the present study, microfluorometric technique was used to evaluate the role of amino acids, glucagon, ryanodine and caffeine on the generation and maintenance of [Ca2+] i oscillations and transients in individual murine β-cells and isolated mouse pancreatic islets. The amino acids glycine, alanine and arginine, at around their physiological concentrations, transformed the glucose-induced slow oscillations of [Ca2+] i in isolated mouse β-cells into sustained elevation. Increased Ca2+ entry promoted the reappearance of the slow [Ca2+] i oscillations. The [Ca2+] i oscillations were more resistant to amino acid transformation in intact islets, supporting the idea that cellular interactions are important for maintaining the oscillatory activity. Individual rat β-cells responded to glucose stimulation with slow [Ca2+] i oscillations due to periodic entry of Ca2+ as well as with transients evoked by mobilization of intracellular stores. The [Ca2+] i oscillations in rat β-cells had a slightly lower frequency than those in mouse β-cells and were more easily transformed into sustained elevation in the presence of glucagon or caffeine. The transients of [Ca2+] i were more common in rat than in mouse β-cells and often appeared in synchrony also in cells lacking physical contact. Depolarization enhanced the generation of [Ca2+] i transients. In accordance with the idea that β-cells have functionally active ryanodine receptors, it was found that ryanodine sometimes restored oscillatory activity abolished by caffeine. However, the IP3 receptors are the major Ca2+ release channels both in β-cells from rats and mice. Single β-cells from ob/ob mice did not differ from those of lean controls with regard to frequency, amplitudes and half-widths of the slow [Ca2+] i oscillations. Nevertheless, there was an excessive firing of [Ca2+] i transients in the β-cells from the ob/ob mice, which was suppressed by leptin at close to physiological concentrations. The enhanced firing of [Ca2+] i transients in ob/ob mouse β-cells may be due to the absence of leptin and mediated by activation of the phospholipase C signaling pathway.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis , 2001. , p. 40
Series
Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine, ISSN 0282-7476 ; 1064
Keywords [en]
Cell biology, pancreatic β-cells, islets of Langerhans, glucose, Ca2+ oscillations, Ca2+ transients, potassium, ryanodine, caffeine, glucagon, cAMP, inositol 1, 4, 5-trisphosphate, fura-2, glycine, alanine, arginine, Ca2+ channels, rats, lean mice, ob/ob mice, leptin
Keywords [sv]
Cellbiologi
National Category
Cell and Molecular Biology
Research subject
Medical Cell Biology
Identifiers
URN: urn:nbn:se:uu:diva-1408ISBN: 91-554-5084-9 (print)OAI: oai:DiVA.org:uu-1408DiVA, id: diva2:160918
Public defence
2001-09-26, lecture room C8:301, Biomedical Center (BMC), Uppsala, 09:15
Opponent
Available from: 2001-10-04 Created: 2001-10-04 Last updated: 2018-01-13Bibliographically approved

Open Access in DiVA

fulltext(1124 kB)1201 downloads
File information
File name FULLTEXT01.pdfFile size 1124 kBChecksum SHA-1
7b7c188f882b9a64702152cd9ee42587f4af7cde4cdc9cc3142ef77d220e5aad322a8dc1
Type fulltextMimetype application/pdf
Buy this publication >>

By organisation
Department of Medical Cell Biology
Cell and Molecular Biology

Search outside of DiVA

GoogleGoogle Scholar
Total: 1201 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 1155 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf