Nusser Z, Sieghart W, Benke D, Fritschy J M, Somogyi P
Anatomical Neuropharmacology Unit, University of Oxford, United Kingdom.
Proc Natl Acad Sci U S A. 1996 Oct 15;93(21):11939-44. doi: 10.1073/pnas.93.21.11939.
Hippocampal pyramidal cells, receiving domain specific GABAergic inputs, express up to 10 different subunits of the gamma-aminobutyric acid type A (GABAA) receptor, but only 3 different subunits are needed to form a functional pentameric channel. We have tested the hypothesis that some subunits are selectively located at subsets of GABAergic synapses. The alpha 1 subunit has been found in most GABAergic synapses on all postsynaptic domains of pyramidal cells. In contrast, the alpha 2 subunit was located only in a subset of synapses on the somata and dendrites, but in most synapses on axon initial segments innervated by axo-axonic cells. The results demonstrate that molecular specialization in the composition of postsynaptic GABAA receptor subunits parallels GABAergic cell specialization in targeting synapses to a specific domain of postsynaptic cortical neurons.
海马锥体细胞接收特定区域的γ-氨基丁酸能输入，表达多达10种不同的A型γ-氨基丁酸（GABAA）受体亚基，但形成功能性五聚体通道仅需3种不同亚基。我们检验了这样一种假说，即某些亚基选择性地定位于γ-氨基丁酸能突触的特定子集。已发现α1亚基存在于锥体细胞所有突触后区域的大多数γ-氨基丁酸能突触中。相比之下，α2亚基仅位于胞体和树突上的一部分突触中，但在轴突-轴突细胞支配的轴突起始段的大多数突触中存在。结果表明，突触后GABAA受体亚基组成的分子特化与γ-氨基丁酸能细胞将突触靶向突触后皮质神经元特定区域的特化情况相似。
