Distinct subtypes of somatostatin-containing neocortical interneurons revealed in transgenic mice
Distinct subtypes of somatostatin-containing neocortical interneurons revealed in transgenic mice
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DOI：
10.1523/jneurosci.0661-06.2006
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发表时间：
2006-05-10
影响因子：
5.3
通讯作者：
Agmon, Ariel
中科院分区：
文献类型：
--
作者：
Ma, Yunyong;Hu, Hang;Agmon, Ariel
大脑皮层中释放 GABA 的抑制性中间神经元可以根据其神经化学成分、放电模式或轴突靶标进行分类，这是最常见的标准，但使用不同标准的分类是否会集中在相同的神经元亚型上，以及存在多少种这样的亚型，是当前人们广泛关注和争论的问题。为了解决这些问题，我们培育了在 GAD67 启动子控制下表达绿色荧光蛋白 (GFP) 的转基因小鼠。在其中两个细胞系（称为 X94 和 X98）中，桶状皮质中的 GFP 表达仅限于含有生长抑素 (SOM +) GABA 能中间神经元的子集，类似于之前报道的“GIN”细胞系 (Oliva 等，2000)，但 X94、X98 和 GIN 细胞系中表达 GFP (GFP +) 细胞体的层状分布是不同的且几乎互补。我们比较了三个细胞系中 GFP + 神经元的神经化学含量和轴突分布模式，并详细分析了以全细胞、电流钳模式记录的 150 个神经元的数据集的电生理特性。根据所有标准，X94 和 X98 GFP + 神经元几乎完美分离，而 GIN GFP + 神经元则表现出中间特性。在X98细胞系中，在颗粒下、含钙结合蛋白、1层靶向（“Martinotti”）细胞中发现了GFP表达，这些细胞具有发射低阈值钙尖峰的倾向，而X94 GFP+细胞是具有准快速尖峰特性的口吃中间神经元，驻留在并靶向丘脑受体新皮质层。我们的结论是，先前归因于新皮质 SOM + 中间神经元的大部分变异性可以通过它们自然分组为不同的亚型来解释。
GABA- releasing inhibitory interneurons in the cerebral cortex can be classified by their neurochemical content, firing patterns, or axonal targets, to name the most common criteria, but whether classifications using different criteria converge on the same neuronal subtypes, and how many such subtypes exist, is a matter of much current interest and considerable debate. To address these issues, we generated transgenic mice expressing green fluorescent protein ( GFP) under control of the GAD67 promoter. In two of these lines, named X94 and X98, GFP expression in the barrel cortex was restricted to subsets of somatostatin- containing ( SOM +) GABAergic interneurons, similar to the previously reported " GIN" line ( Oliva et al., 2000), but the laminar distributions of GFP- expressing ( GFP +) cell bodies in the X94, X98, and GIN lines were distinct and nearly complementary. We compared neurochemical content and axonal distribution patterns of GFP + neurons among the three lines and analyzed in detail electrophysiological properties in a dataset of 150 neurons recorded in whole- cell, current- clamp mode. By all criteria, there was nearly perfect segregation of X94 and X98 GFP + neurons, whereas GIN GFP + neurons exhibited intermediate properties. In the X98 line, GFP expression was found in infragranular, calbindin- containing, layer 1- targeting (" Martinotti") cells that had a propensity to fire low- threshold calcium spikes, whereas X94 GFP + cells were stuttering interneurons with quasi fast- spiking properties, residing in and targeting the thalamo- recipient neocortical layers. We conclude that much of the variability previously attributed to neocortical SOM + interneurons can be accounted for by their natural grouping into distinct subtypes.