Semyanov Alexey, Walker Matthew C, Kullmann Dimitri M
Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK.
Nat Neurosci. 2003 May;6(5):484-90. doi: 10.1038/nn1043.
GABA(A) receptors can mediate both 'phasic' synaptic inhibition and a persistent 'tonic' form of signaling. We show that, in the presence of intact GABA uptake, guinea pig hippocampal interneurons, but not pyramidal cells, express a tonic GABA(A) receptor-mediated conductance. This conductance was pharmacologically distinct from spontaneous inhibitory postsynaptic currents (IPSCs). Inhibiting GABA uptake resulted in the expression of a comparable GABA(A) receptor-mediated tonic conductance in pyramidal cells. Reducing the tonic conductance in interneurons enhanced their excitability and the inhibitory drive to pyramidal cells. These results point to a role for cell type-dependent tonic inhibition in regulating cortical excitability.
γ-氨基丁酸A型（GABA(A)）受体既能介导“相位性”突触抑制，也能介导持续的“紧张性”信号传导形式。我们发现，在完整的γ-氨基丁酸（GABA）摄取存在的情况下，豚鼠海马中间神经元而非锥体细胞表达一种由紧张性GABA(A)受体介导的电导。这种电导在药理学上与自发性抑制性突触后电流（IPSCs）不同。抑制GABA摄取导致锥体细胞中表达类似的由GABA(A)受体介导的紧张性电导。降低中间神经元的紧张性电导会增强它们的兴奋性以及对锥体细胞的抑制驱动。这些结果表明细胞类型依赖性紧张性抑制在调节皮质兴奋性中发挥作用。
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