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Polysynaptic excitatory pathways induce heterosynaptic depression in the rat auditory cortex.

R M Shin·K Kato·K Mikoshiba
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Abstract

Short-term plasticity, the effect of a preceding synaptic response on the following response in a pair, in layers II/III of the rat auditory cortex slice after application of repetitive stimuli to layer IV, was investigated using a multichannel extracellular recording system. Paired-pulse depression, which is induced to a moderate degree in standard artificial cerebrospinal fluid, was markedly facilitated in the presence of bicuculline, a GABA(A) receptor antagonist, concurrent with the emergence of a polysynaptic component of the EPSP (polyEPSP) in the first response in a pair. This depression (bicuculline-facilitated synaptic depression, BFSD) was maximal at the minimum interval tested (50 ms), reduced as the interval was increased, and persisted beyond an interval of 2 s. The occurrence of BFSD was dependent on the presence of a polyEPSP regardless of the presence of the monosynaptic component of the EPSP, indicating that BFSD is induced by a heterosynaptic mechanism. D-AP5, an NMDA receptor antagonist, partially eliminated polyEPSPs and reversed BFSD. These results suggest that activation of polysynaptic excitatory pathways induces a heterosynaptic depression in the range of a few seconds and that NMDA receptor activity is involved in this heterosynaptic depression.

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2-Amino-5-phosphonovalerateAnimalsAuditory CortexBaclofenBicucullineElectric StimulationExcitatory Amino Acid AntagonistsExcitatory Postsynaptic PotentialsFemaleGABA AntagonistsMaleNeural InhibitionNeural PathwaysNeuronal PlasticityPyramidal CellsRatsRats, Sprague-DawleyReceptors, GABAReceptors, Metabotropic GlutamateReceptors, N-Methyl-D-AspartateSynapsesSynaptic TransmissionJournal ArticleResearch Support, Non-U.S. Gov't

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BibTeXRIS

R M Shin, K Kato, K Mikoshiba. 2001. Polysynaptic excitatory pathways induce heterosynaptic depression in the rat auditory cortex.. https://doi.org/10.1016/s0168-0102(01)00213-9

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