Perez Y, Morin F, Lacaille J C
Département de Physiologie, Centre de Recherche en Sciences Neurologiques, Université de Montréal, Case Postale 6128, Succursale Centre-ville, Montréal, QC, Canada H3C 3J7.
Proc Natl Acad Sci U S A. 2001 Jul 31;98(16):9401-6. doi: 10.1073/pnas.161493498. Epub 2001 Jul 10.
Hippocampal inhibitory interneurons play important roles in controlling the excitability and synchronization of pyramidal cells, but whether they express long-term synaptic plasticity that contributes to hippocampal network function remains uncertain. We found that pairing postsynaptic depolarization with theta-burst stimulation induced long-term potentiation (LTP) of putative single-fiber excitatory postsynaptic currents in interneurons. Either postsynaptic depolarization or theta-burst stimulation alone failed to induce LTP. LTP was expressed as a decrease in failure rates and an increase in excitatory postsynaptic current amplitude, independent of N-methyl-d-aspartate receptors, and dependent on metabotropic glutamate receptors subtype 1a. LTP was induced specifically in interneurons in stratum oriens and not in interneurons of stratum radiatum/lacunosum-moleculare. Thus, excitatory synapses onto specific subtypes of inhibitory interneurons express a new form of hebbian LTP that will contribute to hippocampal network plasticity.
海马体抑制性中间神经元在控制锥体细胞的兴奋性和同步性方面发挥着重要作用，但它们是否表达有助于海马体网络功能的长期突触可塑性仍不确定。我们发现，将突触后去极化与θ波爆发刺激配对可诱导中间神经元中假定的单纤维兴奋性突触后电流的长期增强（LTP）。单独的突触后去极化或θ波爆发刺激均未能诱导LTP。LTP表现为失败率降低和兴奋性突触后电流幅度增加，与N-甲基-D-天冬氨酸受体无关，而依赖于代谢型谷氨酸受体亚型1a。LTP特异性地在海马体原层的中间神经元中诱导产生，而不是在海马体辐射层/分子层的中间神经元中诱导产生。因此，兴奋性突触到特定亚型的抑制性中间神经元上表达了一种新形式的赫布型LTP，这将有助于海马体网络可塑性。
