Keller A, White E L
J Comp Neurol. 1987 Aug 1;262(1):1-12. doi: 10.1002/cne.902620102.
Immunocytochemical methods were used to examine GABAergic neurons in the barrel region of the mouse primary somatosensory cortex. GABAergic neurons occur in all layers of the barrel cortex but are more concentrated in the upper portion of layers II/III and in layers IV and VI. Nine cells in layer IV were examined with the electron microscope, and portions of their dendrites were reconstructed from serial thin sections. These cells are of the nonspiny, multipolar or bitufted varieties, and some of them have beaded dendrites. The labeled cell bodies and their reconstructed dendrites were postsynaptic at asymmetrical synapses with thalamocortical axon terminals labeled by lesion-induced degeneration and with unlabeled axon terminals. Each cell also received symmetrical synapses from GABAergic axon terminals and from unlabeled axon terminals. Our results indicate that GABAergic cell bodies and processes receive synapses from thalamocortical axon terminals but that different cells display marked differences in the proportion of thalamocortical and other synapses they receive. These results indicate that GABAergic cells form a heterogeneous population with respect to their morphologies and patterns of synaptic inputs. The synaptic sequences revealed here for GABAergic neurons represent an anatomical substrate for various inhibitory processes known to occur within the cerebral cortex.
采用免疫细胞化学方法检测小鼠初级体感皮层桶状区的γ-氨基丁酸（GABA）能神经元。GABA能神经元存在于桶状皮层的所有层中，但在II/III层上部以及IV层和VI层中更为集中。对IV层中的9个细胞进行了电子显微镜检查，并从连续的薄切片中重建了它们的部分树突。这些细胞属于无棘、多极或双簇状类型，其中一些具有串珠状树突。标记的细胞体及其重建的树突在与通过损伤诱导变性标记的丘脑皮质轴突终末以及未标记的轴突终末形成的不对称突触处为突触后。每个细胞还接受来自GABA能轴突终末和未标记轴突终末的对称突触。我们的结果表明，GABA能细胞体和突起接受来自丘脑皮质轴突终末的突触，但不同细胞在接受的丘脑皮质和其他突触比例上表现出明显差异。这些结果表明，GABA能细胞在形态和突触输入模式方面形成了一个异质群体。这里揭示的GABA能神经元的突触序列代表了已知发生在大脑皮层内的各种抑制过程的解剖学基础。
