Advanced

Synapsins I and II Are Not Required for Insulin Secretion from Mouse Pancreatic beta-cells

Wendt, Anna LU ; Speidel, Dina LU ; Danielsson, Anders LU ; Esguerra, Jonathan L. S.; Bogen, Inger Lise; Walaas, S. Ivar; Salehi, S Albert LU and Eliasson, Lena LU (2012) In Endocrinology 153(5). p.2112-2119
Abstract
Synapsins are a family of phosphoproteins that modulate the release of neurotransmitters from synaptic vesicles. The release of insulin from pancreatic beta-cells has also been suggested to be regulated by synapsins. In this study, we have utilized a knock out mouse model with general disruptions of the synapsin I and II genes [synapsin double knockout (DKO)]. Stimulation with 20 mM glucose increased insulin secretion 9-fold in both wild-type (WT) and synapsin DKO islets, whereas secretion in the presence of 70 mM K+ and 1mM glucose was significantly enhanced in the synapsin DKO mice compared to WT. Exocytosis in single beta-cells was investigated using patch clamp. The exocytotic response, measured by capacitance measurements and elicited... (More)
Synapsins are a family of phosphoproteins that modulate the release of neurotransmitters from synaptic vesicles. The release of insulin from pancreatic beta-cells has also been suggested to be regulated by synapsins. In this study, we have utilized a knock out mouse model with general disruptions of the synapsin I and II genes [synapsin double knockout (DKO)]. Stimulation with 20 mM glucose increased insulin secretion 9-fold in both wild-type (WT) and synapsin DKO islets, whereas secretion in the presence of 70 mM K+ and 1mM glucose was significantly enhanced in the synapsin DKO mice compared to WT. Exocytosis in single beta-cells was investigated using patch clamp. The exocytotic response, measured by capacitance measurements and elicited by a depolarization protocol designed to visualize exocytosis of vesicles from the readily releasable pool and from the reserve pool, was of the same size in synapsin DKO and WT beta-cells. The increase in membrane capacitance corresponding to readily releasable pool was approximately 50fF in both genotypes. We next investigated the voltage-dependent Ca2+ influx. In both WT and synapsin DKO beta-cells the Ca2+ current peaked at 0 mV and measured peak current (I-p) and net charge (Q) were of similar magnitude. Finally, ultrastructural data showed no variation in total number of granules (N-v) or number of docked granules (N-s) between the beta-cells from synapsin DKO mice and WT control. We conclude that neither synapsin I nor synapsin II are directly involved in the regulation of glucose-stimulated insulin secretion and Ca-2-dependent exocytosis in mouse pancreatic beta-cells. (Endocrinology 153: 2112-2119, 2012) (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Endocrinology
volume
153
issue
5
pages
2112 - 2119
publisher
Endocrine Society
external identifiers
  • wos:000303860700011
  • pmid:22334712
  • scopus:84860351783
ISSN
0013-7227
DOI
10.1210/en.2011-1702
language
English
LU publication?
yes
id
61fb0034-0166-402b-83d4-e320346e614e (old id 2812998)
date added to LUP
2012-07-03 10:26:50
date last changed
2017-09-17 03:24:30
@article{61fb0034-0166-402b-83d4-e320346e614e,
  abstract     = {Synapsins are a family of phosphoproteins that modulate the release of neurotransmitters from synaptic vesicles. The release of insulin from pancreatic beta-cells has also been suggested to be regulated by synapsins. In this study, we have utilized a knock out mouse model with general disruptions of the synapsin I and II genes [synapsin double knockout (DKO)]. Stimulation with 20 mM glucose increased insulin secretion 9-fold in both wild-type (WT) and synapsin DKO islets, whereas secretion in the presence of 70 mM K+ and 1mM glucose was significantly enhanced in the synapsin DKO mice compared to WT. Exocytosis in single beta-cells was investigated using patch clamp. The exocytotic response, measured by capacitance measurements and elicited by a depolarization protocol designed to visualize exocytosis of vesicles from the readily releasable pool and from the reserve pool, was of the same size in synapsin DKO and WT beta-cells. The increase in membrane capacitance corresponding to readily releasable pool was approximately 50fF in both genotypes. We next investigated the voltage-dependent Ca2+ influx. In both WT and synapsin DKO beta-cells the Ca2+ current peaked at 0 mV and measured peak current (I-p) and net charge (Q) were of similar magnitude. Finally, ultrastructural data showed no variation in total number of granules (N-v) or number of docked granules (N-s) between the beta-cells from synapsin DKO mice and WT control. We conclude that neither synapsin I nor synapsin II are directly involved in the regulation of glucose-stimulated insulin secretion and Ca-2-dependent exocytosis in mouse pancreatic beta-cells. (Endocrinology 153: 2112-2119, 2012)},
  author       = {Wendt, Anna and Speidel, Dina and Danielsson, Anders and Esguerra, Jonathan L. S. and Bogen, Inger Lise and Walaas, S. Ivar and Salehi, S Albert and Eliasson, Lena},
  issn         = {0013-7227},
  language     = {eng},
  number       = {5},
  pages        = {2112--2119},
  publisher    = {Endocrine Society},
  series       = {Endocrinology},
  title        = {Synapsins I and II Are Not Required for Insulin Secretion from Mouse Pancreatic beta-cells},
  url          = {http://dx.doi.org/10.1210/en.2011-1702},
  volume       = {153},
  year         = {2012},
}