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Please use this identifier to cite or link to this item: http://hdl.handle.net/1942/9432

Title: Heterogeneity of postsynaptic receptor occupancy fluctuations among glycinergic inhibitory synapses in the zebrafish hindbrain
Authors: RIGO, Jean-Michel
Badiu, C.L.
Legendre, P.
Issue Date: 2003
Citation: JOURNAL OF PHYSIOLOGY-LONDON, 553(3). p. 819-832
Abstract: The amplitude of glycinergic miniature inhibitory postsynaptic currents (mIPSCs) varies considerably in neurons recorded in the isolated hindbrain of 50-h-old zebrafish larvae. At this age, glycinergic synapses are functionally mature. In order to measure the occupancy level of postsynaptic glycine receptors (GlyRs) and to determine the pre- and/or postsynaptic origin of its variability, we analysed mIPSCs within bursts evoked by alpha-latrotoxin (0.1-1 nM). Two types of burst were observed according to their mIPSC frequencies: 'slow' bursts with clearly spaced mIPSCs and 'fast' bursts characterised by superimposed events. Non-stationary noise analysis of mIPSCs in some 'slow' bursts recorded in the presence or in the absence of Ca2+ denoted that mIPSC amplitude variance did not depend on the quantity of neurotransmitters released (presynaptic origin), but rather on intrinsic stochastic behaviour of the same group of GlyRs (postsynaptic origin). In these bursts, the open probability measured at the peak of the mIPSCs was close to 0.5 while the maximum open probability is close to 0.9 for the synaptic isoform of GlyRs (heteromeric alpha1/beta GlyRs). In 'fast' bursts with superimposed events, a correlation was found between the amplitude of mIPSCs and the basal current level measured at their onset, which could suggest that the same group of GlyRs is activated during such bursts. Altogether, our results indicate that glycine synapses can display different release modes in the presence of alpha-latrotoxin. They also indicate that, in our model, postsynaptic GlyRs cannot be saturated by the release of a single vesicle.
Notes: Univ Paris 06, CNRS, UMR 7102, Lab Dynam Synapse, F-75252 Paris 05, France. Univ Liege, Ctr Cellular & Mol Neurobiol, B-4020 Liege, Belgium.
URI: http://hdl.handle.net/1942/9432
DOI: 10.1113/jphysiol.2003.049577
ISI #: 000188066200012
ISSN: 0022-3751
Category: A1
Type: Journal Contribution
Appears in Collections: Research publications

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