Gu J G, Albuquerque C, Lee C J, MacDermott A B
Department of Physiology and Cellular Biophysics, Columbia University, New York, 10032, USA.
Nature. 1996 Jun 27;381(6585):793-6. doi: 10.1038/381793a0.
Postsynaptic Ca2+ elevation during synaptic transmission is an important trigger for short- and long-term changes in synaptic strength in the vertebrate central nervous system. The AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazoleproprionate) receptors, a subfamily of glutamate receptors, mediate much of the excitatory synaptic transmission in the brain and spinal cord. It has been shown that a subtype of the AMPA receptor is Ca2+-permeable and is present in the subpopulations of neurons. When synaptically localized, these receptors should mediate postsynaptic Ca2+ influx, providing a trigger for changes in synaptic strength. Here we show that Ca2+-permeable AMPA receptors are synaptically localized on a subpopulation of dorsal horn neurons, and that they provide a synaptically gated route of Ca2+ entry, and that activation of these receptors strengthens synaptic transmission mediated by AMPA receptors. This pathway for postsynaptic Ca2+ influx may provide a new form of activity-dependent modulation of synaptic strength.
在脊椎动物中枢神经系统中，突触传递过程中突触后Ca2+浓度升高是突触强度短期和长期变化的重要触发因素。AMPA（α-氨基-3-羟基-5-甲基-4-异恶唑丙酸）受体是谷氨酸受体的一个亚家族，介导大脑和脊髓中的大部分兴奋性突触传递。研究表明，AMPA受体的一种亚型具有Ca2+通透性，存在于神经元亚群中。当定位于突触时，这些受体应介导突触后Ca2+内流，为突触强度的变化提供触发因素。在这里，我们表明，Ca2+通透性AMPA受体突触定位在背角神经元的一个亚群上，它们提供了一条Ca2+进入的突触门控途径，并且这些受体的激活增强了由AMPA受体介导的突触传递。这种突触后Ca2+内流途径可能提供一种新的依赖于活动的突触强度调节形式。
