Stepanyuk Andrey R, Borisyuk Anya L, Tsugorka Tetiana M, Belan Pavel V
Department of General Physiology of the Nervous System, Bogomoletz Institute of Physiology, 4 Bogomoletz street, Kiev, 01024, Ukraine; State Key Laboratory of Molecular and Cellular Biology, Bogomoletz Institute of Physiology, 4 Bogomoletz street, Kiev, 01024, Ukraine.
Synapse. 2014 Aug;68(8):344-54. doi: 10.1002/syn.21742. Epub 2014 Apr 8.
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.
同一轴突的突触之间，短期突触可塑性模式可能存在显著差异。这可能导致传递低频或高频信号的突触受体分离，因此可能对大脑中的信息传递产生功能影响。在这里，我们使用一种依赖于使用的GABAA受体拮抗剂苦味毒素，来选择性抑制在低频刺激期间单突触激活的GABAA受体池，从而评估海马GABA能突触处这种分离的程度。高频刺激前后诱发的突触后反应的相对变化，被用来评估该GABAA受体池对高频突触传递的贡献。使用这种方法，我们已经表明，低频（0.2 Hz）刺激诱发的抑制性突触后电流（IPSCs）和高频（20 - 40 Hz）刺激诱发的异步电流，是由不同的突触后GABAA受体池介导的。因此，我们的研究结果表明，单个海马中间神经元产生的抑制作用可能会根据突触前放电频率，选择性地导向不同的突触后靶点。
