Oleskevich S, Alvarez F J, Walmsley B
The Synaptic Structure and Function Group, Division of Neuroscience, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT 0200, Australia.
J Neurophysiol. 1999 Jul;82(1):312-9. doi: 10.1152/jn.1999.82.1.312.
The structural features of a synaptic connection between central neurons play an important role in determining the strength of the connection. In the present study, we have examined the relationship between the structural and functional properties of glycinergic synapses in the rat spinal cord. We have analyzed the structure of glycinergic receptor clusters on rat ventral horn interneurons using antibodies against the glycine receptor clustering protein, gephyrin. We have examined the properties of quantal glycinergic currents generated at these synapses using whole cell patch-clamp recordings of miniature postsynaptic inhibitory currents (mIPSCs) in rat spinal cord slices in vitro. Our immunolabeling results demonstrate that there is a considerable variability in the size of glycine receptor clusters within individual neurons. Furthermore there are large differences in the mean cluster size between neurons. These observations are paralleled closely by recordings of glycinergic mIPSCs. The mIPSC amplitude varies significantly within and between neurons. Results obtained using combined immunolabeling and electrophysiological recording on the same neurons show that cells with small glycine receptor clusters concurrently exhibit small mIPSCs. Our results suggest that the differences in the size of glycinergic receptor clusters may constitute an important factor contributing to the observed differences in mIPSC amplitude among spinal cord interneurons.
中枢神经元之间突触连接的结构特征在决定连接强度方面起着重要作用。在本研究中，我们研究了大鼠脊髓中甘氨酸能突触的结构和功能特性之间的关系。我们使用针对甘氨酸受体聚集蛋白桥连蛋白的抗体，分析了大鼠腹角中间神经元上甘氨酸能受体簇的结构。我们通过对体外大鼠脊髓切片中微小突触后抑制性电流（mIPSCs）进行全细胞膜片钳记录，研究了这些突触处产生的量子化甘氨酸能电流的特性。我们的免疫标记结果表明，单个神经元内甘氨酸受体簇的大小存在相当大的变异性。此外，神经元之间的平均簇大小存在很大差异。这些观察结果与甘氨酸能mIPSCs的记录密切平行。mIPSC幅度在神经元内和神经元之间有显著变化。在同一神经元上使用联合免疫标记和电生理记录获得的结果表明，甘氨酸受体簇小的细胞同时表现出小的mIPSCs。我们的结果表明，甘氨酸能受体簇大小的差异可能是导致脊髓中间神经元之间观察到的mIPSC幅度差异的一个重要因素。
