Fast insulin secretion reflects exocytosis of docked granules in mouse pancreatic B-cells.
Olofsson, Charlotta LU ; Göpel, Sven LU ; Barg, Sebastian LU ; Galvanovskis, Juris LU ; Ma, Xiaosong LU ; Salehi, Albert ; Rorsman, Patrik LU and Eliasson, Lena LU
(2002)
In Pflügers Archiv
444(1-2).
p.43-51
- Abstract
- A readily releasable pool (RRP) of granules has been proposed to underlie the first phase of insulin secretion. In the present study we combined electron microscopy, insulin secretion measurements and recordings of cell capacitance in an attempt to define this pool ultrastructurally. Mouse pancreatic B-cells contain approximately 9,000 granules, of which 7% are docked below the plasma membrane. The number of docked granules was reduced by 30% (200 granules) during 10 min stimulation with high K+. This stimulus depolarized the cell to -10 mV, elevated cytosolic [Ca2+] ([Ca2+](i)) from a basal concentration of 130 nM to a peak of 1.3 microM and released 0.5 ng insulin/islet, corresponding to 200-300 granules/cell. The Ca2+ transient decayed... (More)
- A readily releasable pool (RRP) of granules has been proposed to underlie the first phase of insulin secretion. In the present study we combined electron microscopy, insulin secretion measurements and recordings of cell capacitance in an attempt to define this pool ultrastructurally. Mouse pancreatic B-cells contain approximately 9,000 granules, of which 7% are docked below the plasma membrane. The number of docked granules was reduced by 30% (200 granules) during 10 min stimulation with high K+. This stimulus depolarized the cell to -10 mV, elevated cytosolic [Ca2+] ([Ca2+](i)) from a basal concentration of 130 nM to a peak of 1.3 microM and released 0.5 ng insulin/islet, corresponding to 200-300 granules/cell. The Ca2+ transient decayed towards the prestimulatory concentration within approximately 200 s, presumably reflecting Ca2+ channel inactivation. Renewed stimulation with high K+ failed to stimulate insulin secretion when applied in the absence of glucose. The size of the RRP, derived from the insulin measurements, is similar to that estimated from the increase in cell capacitance elicited by photolytic release of caged Ca2+. We propose that the RRP represents a subset of the docked pool of granules and that replenishment of RRP can be accounted for largely by chemical modification of granules already in place or situated close to the plasma membrane. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/107824
- author
- Olofsson, Charlotta
LU
; Göpel, Sven
LU
; Barg, Sebastian
LU
; Galvanovskis, Juris
LU
; Ma, Xiaosong
LU
; Salehi, Albert
; Rorsman, Patrik
LU
and Eliasson, Lena
LU
- organization
- publishing date
- 2002
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Pflügers Archiv
- volume
- 444
- issue
- 1-2
- pages
- 43 - 51
- publisher
- Springer
- external identifiers
-
- pmid:11976915
- wos:000175781400004
- scopus:0036261251
- ISSN
- 0031-6768
- DOI
- 10.1007/s00424-002-0781-5
- language
- English
- LU publication?
- yes
- id
- e8eb3242-f247-4213-8366-6272690c9602 (old id 107824)
- alternative location
- http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11976915&dopt=Abstract
- date added to LUP
- 2016-04-01 15:19:16
- date last changed
- 2022-04-22 07:09:36
@article{e8eb3242-f247-4213-8366-6272690c9602,
abstract = {{A readily releasable pool (RRP) of granules has been proposed to underlie the first phase of insulin secretion. In the present study we combined electron microscopy, insulin secretion measurements and recordings of cell capacitance in an attempt to define this pool ultrastructurally. Mouse pancreatic B-cells contain approximately 9,000 granules, of which 7% are docked below the plasma membrane. The number of docked granules was reduced by 30% (200 granules) during 10 min stimulation with high K+. This stimulus depolarized the cell to -10 mV, elevated cytosolic [Ca2+] ([Ca2+](i)) from a basal concentration of 130 nM to a peak of 1.3 microM and released 0.5 ng insulin/islet, corresponding to 200-300 granules/cell. The Ca2+ transient decayed towards the prestimulatory concentration within approximately 200 s, presumably reflecting Ca2+ channel inactivation. Renewed stimulation with high K+ failed to stimulate insulin secretion when applied in the absence of glucose. The size of the RRP, derived from the insulin measurements, is similar to that estimated from the increase in cell capacitance elicited by photolytic release of caged Ca2+. We propose that the RRP represents a subset of the docked pool of granules and that replenishment of RRP can be accounted for largely by chemical modification of granules already in place or situated close to the plasma membrane.}},
author = {{Olofsson, Charlotta and Göpel, Sven and Barg, Sebastian and Galvanovskis, Juris and Ma, Xiaosong and Salehi, Albert and Rorsman, Patrik and Eliasson, Lena}},
issn = {{0031-6768}},
language = {{eng}},
number = {{1-2}},
pages = {{43--51}},
publisher = {{Springer}},
series = {{Pflügers Archiv}},
title = {{Fast insulin secretion reflects exocytosis of docked granules in mouse pancreatic B-cells.}},
url = {{http://dx.doi.org/10.1007/s00424-002-0781-5}},
doi = {{10.1007/s00424-002-0781-5}},
volume = {{444}},
year = {{2002}},
}