The role of GABAAR subunits in determining the time course of mIPSCs
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1
Hungarian Academy of Sciences, Institute of Experimental Medicine, Hungary
GABAergic neurotransmission is ubiquitous in the brain, controlling fundamental cellular processes such as shunting inhibition and network oscillations at different frequencies. The subunit composition of GABAA receptors (GABAAR) strongly affects the deactivation kinetics of GABA-evoked currents in recombinant systems, but it is less clear how it affects IPSC kinetics in situ. We addressed this issue by combining whole-cell recordings of miniature IPSCs with quantitative immunolocalization of synaptic GABAAR subunits. Neurons expressing only the α1 as synaptic α subunit have Zolpidem-sensitive mIPSCs with weighted decay time constants (τw) of 4-5 ms. Two other neuron types expressing only the α2 or the α3 as synaptic α subunit both exhibited slow, Zolpidem-insensitive mIPSCs with τw of 20 and 28 ms, respectively. In contrast, external tufted cells of the main olfactory bulb express two α subunit variants (α1 and α3) in their synapses. Quantitative analysis of confocal images revealed small within-cell, but large between-cell variability in synaptic α1/α3 subunit ratios. Whole-cell recordings demonstrated a small within-cell, but large between-cell variability in the decay of mIPSCs (τw varied from 3 to 30 ms) and the Zolpidem sensitivity correlated with τw. These results reveal that by mixing two subunits that confer very different τw, the kinetics of synaptic currents in individual cells can be tuned to any intermediate point within the whole range.
Keywords:
Neurophysiology,
Neuroscience
Conference:
13th Conference of the Hungarian Neuroscience Society (MITT), Budapest, Hungary, 20 Jan - 22 Jan, 2011.
Presentation Type:
Abstract
Topic:
Neurophysiology
Citation:
Eyre
MD and
Nusser
Z
(2011). The role of GABAAR subunits in determining the time course of mIPSCs.
Front. Neurosci.
Conference Abstract:
13th Conference of the Hungarian Neuroscience Society (MITT).
doi: 10.3389/conf.fnins.2011.84.00113
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Received:
03 Mar 2011;
Published Online:
23 Mar 2011.
*
Correspondence:
Dr. M. D Eyre, Hungarian Academy of Sciences, Institute of Experimental Medicine, Budapest, Hungary, eyre@koki.hu