Isa T, Iino M, Ozawa S
Department of Integrative Physiology, National Institute for Physiological Sciences, Okazaki, Japan.
Neuroreport. 1996 Feb 29;7(3):689-92. doi: 10.1097/00001756-199602290-00002.
AMPA-gated glutamate receptors with outward rectification (type I receptors) are almost impermeable to Ca2+, while those with strong inward rectification (type II receptors) have high Ca2+ permeability. In the present study current responses in rat hippocampal neurones mediated by type II AMPA receptors were blocked by application of spermine to the external solution (IC50 = 170 microM), but those mediated by type I AMPA receptors were not affected. Furthermore, in putative non-pyramidal neurones in rat hippocampal slices, EPSCs mediated by type II AMPA receptors were markedly reduced by 1mM spermine, while those mediated by type I AMPA receptors were much less affected. Thus, external spermine exerts differential blocking action on the two different types of AMPA receptors.
具有外向整流特性的AMPA门控谷氨酸受体（I型受体）对Ca2+几乎不通透，而具有强内向整流特性的受体（II型受体）则具有高Ca2+通透性。在本研究中，向外部溶液中加入精胺可阻断大鼠海马神经元中由II型AMPA受体介导的电流反应（IC50 = 170 microM），但由I型AMPA受体介导的电流反应不受影响。此外，在大鼠海马切片中假定的非锥体神经元中，1mM精胺可显著降低由II型AMPA受体介导的兴奋性突触后电流（EPSCs），而由I型AMPA受体介导的EPSCs受影响较小。因此，外部精胺对两种不同类型的AMPA受体具有不同的阻断作用。
