Regulated Exocytosis of GABA-containing Synaptic-like Microvesicles in Pancreatic {beta}-cells.
(2004) In Journal of General Physiology 123(3). p.191-204- Abstract
- We have explored whether {gamma}-aminobutyric acid (GABA) is released by regulated exocytosis of GABA-containing synaptic-like microvesicles (SLMVs) in insulin-releasing rat pancreatic ß-cells. To this end, ß-cells were engineered to express GABAA-receptor Cl--channels at high density using adenoviral infection. Electron microscopy indicated that the average diameter of the SLMVs is 90 nm, that every ß-cell contains ~3,500 such vesicles, and that insulin-containing large dense core vesicles exclude GABA. Quantal release of GABA, seen as rapidly activating and deactivating Cl--currents, was observed during membrane depolarizations from -70 mV to voltages beyond -40 mV or when Ca2+ was dialysed into the cell interior. Depolarization-evoked... (More)
- We have explored whether {gamma}-aminobutyric acid (GABA) is released by regulated exocytosis of GABA-containing synaptic-like microvesicles (SLMVs) in insulin-releasing rat pancreatic ß-cells. To this end, ß-cells were engineered to express GABAA-receptor Cl--channels at high density using adenoviral infection. Electron microscopy indicated that the average diameter of the SLMVs is 90 nm, that every ß-cell contains ~3,500 such vesicles, and that insulin-containing large dense core vesicles exclude GABA. Quantal release of GABA, seen as rapidly activating and deactivating Cl--currents, was observed during membrane depolarizations from -70 mV to voltages beyond -40 mV or when Ca2+ was dialysed into the cell interior. Depolarization-evoked GABA release was suppressed when Ca2+ entry was inhibited using Cd2+. Analysis of the kinetics of GABA release revealed that GABA-containing vesicles can be divided into a readily releasable pool and a reserve pool. Simultaneous measurements of GABA release and cell capacitance indicated that exocytosis of SLMVs contributes ~1% of the capacitance signal. Mathematical analysis of the release events suggests that every SLMV contains 0.36 amol of GABA. We conclude that there are two parallel pathways of exocytosis in pancreatic ß-cells and that release of GABA may accordingly be temporally and spatially separated from insulin secretion. This provides a basis for paracrine GABAergic signaling within the islet. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/120644
- author
- Braun, Matthias ; Wendt, Anna LU ; Birnir, Bryndis ; Broman, Jonas LU ; Eliasson, Lena ; Galvanovskis, Juris ; Gromada, Jesper ; Mulder, Hindrik LU and Rorsman, Patrik
- organization
- publishing date
- 2004
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- GABA, GAD65, pancreatic islets, paracrine communication, SLMV
- in
- Journal of General Physiology
- volume
- 123
- issue
- 3
- pages
- 191 - 204
- publisher
- Rockefeller Institute for Medical Research
- external identifiers
-
- wos:000220024500002
- pmid:14769845
- scopus:1442358665
- pmid:14769845
- ISSN
- 0022-1295
- DOI
- 10.1085/jgp.200308966
- language
- English
- LU publication?
- yes
- id
- addc0ee0-7ee8-4979-8b11-7d565f7f03f9 (old id 120644)
- date added to LUP
- 2016-04-01 16:42:28
- date last changed
- 2022-03-22 20:30:50
@article{addc0ee0-7ee8-4979-8b11-7d565f7f03f9, abstract = {{We have explored whether {gamma}-aminobutyric acid (GABA) is released by regulated exocytosis of GABA-containing synaptic-like microvesicles (SLMVs) in insulin-releasing rat pancreatic ß-cells. To this end, ß-cells were engineered to express GABAA-receptor Cl--channels at high density using adenoviral infection. Electron microscopy indicated that the average diameter of the SLMVs is 90 nm, that every ß-cell contains ~3,500 such vesicles, and that insulin-containing large dense core vesicles exclude GABA. Quantal release of GABA, seen as rapidly activating and deactivating Cl--currents, was observed during membrane depolarizations from -70 mV to voltages beyond -40 mV or when Ca2+ was dialysed into the cell interior. Depolarization-evoked GABA release was suppressed when Ca2+ entry was inhibited using Cd2+. Analysis of the kinetics of GABA release revealed that GABA-containing vesicles can be divided into a readily releasable pool and a reserve pool. Simultaneous measurements of GABA release and cell capacitance indicated that exocytosis of SLMVs contributes ~1% of the capacitance signal. Mathematical analysis of the release events suggests that every SLMV contains 0.36 amol of GABA. We conclude that there are two parallel pathways of exocytosis in pancreatic ß-cells and that release of GABA may accordingly be temporally and spatially separated from insulin secretion. This provides a basis for paracrine GABAergic signaling within the islet.}}, author = {{Braun, Matthias and Wendt, Anna and Birnir, Bryndis and Broman, Jonas and Eliasson, Lena and Galvanovskis, Juris and Gromada, Jesper and Mulder, Hindrik and Rorsman, Patrik}}, issn = {{0022-1295}}, keywords = {{GABA; GAD65; pancreatic islets; paracrine communication; SLMV}}, language = {{eng}}, number = {{3}}, pages = {{191--204}}, publisher = {{Rockefeller Institute for Medical Research}}, series = {{Journal of General Physiology}}, title = {{Regulated Exocytosis of GABA-containing Synaptic-like Microvesicles in Pancreatic {beta}-cells.}}, url = {{https://lup.lub.lu.se/search/files/4756430/623958.pdf}}, doi = {{10.1085/jgp.200308966}}, volume = {{123}}, year = {{2004}}, }