Presynaptic and postsynaptic mechanisms underlie paired pulse depression at single GABAergic boutons in rat collicular cultures
-
Altmetric Citations
Kirischuk, Sergei; Clements, John D; Grantyn, Rosemarie
Description
Paired pulse depression (PPD) is a common form of short-term synaptic plasticity. The aim of this study was to characterise PPD at the level of a single inhibitory bouton. Low-density collicular cultures were loaded with the Ca2+ indicator Oregon Green-1, active boutons were stained with RH414, and action potentials were blocked with TTX. Evoked IPSCs (eIPSCs) and presynaptic Ca2+ transients were recorded in response to direct presynaptic depolarisation of an individual bouton. The single...[Show more]
dc.contributor.author | Kirischuk, Sergei | |
---|---|---|
dc.contributor.author | Clements, John D | |
dc.contributor.author | Grantyn, Rosemarie | |
dc.date.accessioned | 2015-12-13T22:25:35Z | |
dc.date.available | 2015-12-13T22:25:35Z | |
dc.identifier.issn | 0022-3751 | |
dc.identifier.uri | http://hdl.handle.net/1885/73332 | |
dc.description.abstract | Paired pulse depression (PPD) is a common form of short-term synaptic plasticity. The aim of this study was to characterise PPD at the level of a single inhibitory bouton. Low-density collicular cultures were loaded with the Ca2+ indicator Oregon Green-1, active boutons were stained with RH414, and action potentials were blocked with TTX. Evoked IPSCs (eIPSCs) and presynaptic Ca2+ transients were recorded in response to direct presynaptic depolarisation of an individual bouton. The single bouton eIPSCs had a low failure rate (< 0.1), large average quantal content (3-6) and slow decay (τ1 = 15 ms, τ2 = 81 ms). The PPD of eIPSCs had two distinct components: PPDfast and PPDslow (τ = 86 ms and 2 s). PPDslow showed no dependence on extracellular Ca2+ concentration, or on the first eIPSC's failure rate or amplitude. Most probably, it reflects a release-independent inhibition of exocytosis. PPDffast was only observed in normal or elevated Ca2+. It decreased with the failure rate and increased with the amplitude of the first eIPSC. It coincided with paired pulse depression of the presynaptic Ca2+ transients (τ = 120 ms). The decay of the latter was accelerated by EGTA, which also reduced PPDfast. Therefore, a suppressive effect of residual presynaptic Ca2+ on subsequent Ca2+ influx is considered the most likely cause of PPDfast, PPDfast may also have a postsynaptic component, because exposure to a low-affinity GABAA receptor antagonist (TPMPA; 300 μM) counteracted PPDfast and asynchronous IPSC amplitudes were depressed for a short interval following an eIPSC. Thus, at these synapses, PPD is produced by at least two release-independent presynaptic mechanisms and one release-dependent postsynaptic mechanism. | |
dc.publisher | Cambridge University Press | |
dc.source | Journal of Physiology | |
dc.subject | Keywords: 4 aminobutyric acid receptor blocking agent; calcium ion; egtazic acid; 4 aminobutyric acid; 4 aminobutyric acid B receptor; calcium; action potential; animal cell; brain stem; calcium transport; cell culture; controlled study; evoked response; exocytosis | |
dc.title | Presynaptic and postsynaptic mechanisms underlie paired pulse depression at single GABAergic boutons in rat collicular cultures | |
dc.type | Journal article | |
local.description.notes | Imported from ARIES | |
local.description.refereed | Yes | |
local.identifier.citationvolume | 543 | |
dc.date.issued | 2002 | |
local.identifier.absfor | 060105 - Cell Neurochemistry | |
local.identifier.ariespublication | MigratedxPub3648 | |
local.type.status | Published Version | |
local.contributor.affiliation | Kirischuk, Sergei, Humboldt University of Berlin | |
local.contributor.affiliation | Clements, John D, College of Medicine, Biology and Environment, ANU | |
local.contributor.affiliation | Grantyn, Rosemarie, College of Medicine, Biology and Environment, ANU | |
local.bibliographicCitation.issue | 1 | |
local.bibliographicCitation.startpage | 99 | |
local.bibliographicCitation.lastpage | 116 | |
local.identifier.doi | 10.1113/jphysiol.2002.021576 | |
dc.date.updated | 2015-12-11T08:17:17Z | |
local.identifier.scopusID | 2-s2.0-0037101912 | |
Collections | ANU Research Publications |
Download
Items in Open Research are protected by copyright, with all rights reserved, unless otherwise indicated.
Updated: 17 November 2022/ Responsible Officer: University Librarian/ Page Contact: Library Systems & Web Coordinator