Different pools of postsynaptic GABAA receptors mediate inhibition evoked by low- and high-frequency presynaptic stimulation at hippocampal synapses

Authors

  • Andrey R. Stepanyuk,

    1. Department of General Physiology of the Nervous System, Bogomoletz Institute of Physiology, Kiev, Ukraine
    2. State Key Laboratory of Molecular and Cellular Biology, Bogomoletz Institute of Physiology, Kiev, Ukraine
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    • A.R.S. and A.L.B. contributed equally to this work.

  • Anya L. Borisyuk,

    1. Department of General Physiology of the Nervous System, Bogomoletz Institute of Physiology, Kiev, Ukraine
    2. State Key Laboratory of Molecular and Cellular Biology, Bogomoletz Institute of Physiology, Kiev, Ukraine
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    • A.R.S. and A.L.B. contributed equally to this work.

  • Tetiana M. Tsugorka,

    1. Department of General Physiology of the Nervous System, Bogomoletz Institute of Physiology, Kiev, Ukraine
    2. State Key Laboratory of Molecular and Cellular Biology, Bogomoletz Institute of Physiology, Kiev, Ukraine
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  • Pavel V. Belan

    Corresponding author
    1. Department of General Physiology of the Nervous System, Bogomoletz Institute of Physiology, Kiev, Ukraine
    2. State Key Laboratory of Molecular and Cellular Biology, Bogomoletz Institute of Physiology, Kiev, Ukraine
    • Correspondence to: Pavel V. Belan, Department of General Physiology of the Nervous System, Bogomoletz Institute of Physiology, Kiev 01024, Ukraine. E-mail: pasha@biph.kiev.ua

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ABSTRACT

Patterns of short-term synaptic plasticity could considerably differ between synapses of the same axon. This may lead to separation of synaptic receptors transmitting either low- or high-frequency signals and, therefore, may have functional consequences for the information transfer in the brain. Here, we estimated a degree of such separation at hippocampal GABAergic synapses using a use-dependent GABAA receptor antagonist, picrotoxin, to selectively suppress a pool of GABAA receptors monosynaptically activated during the low-frequency stimulation. The relative changes in postsynaptic responses evoked by the high-frequency stimulation before and after such block were used to estimate the contribution of this GABAA receptor pool to synaptic transmission at high frequencies. Using this approach, we have shown that IPSCs evoked by low-frequency (0.2 Hz) stimulation and asynchronous currents evoked by high-frequency (20–40 Hz) stimulation are mediated by different pools of postsynaptic GABAA receptors. Thus, our findings suggest that inhibition produced by a single hippocampal interneuron may be selectively routed to different postsynaptic targets depending on the presynaptic discharge frequency. Synapse 68:344–354, 2014. © 2014 Wiley Periodicals, Inc.

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