Klostermann O, Wahle P
AG Entwicklungsneurobiologie, Fakultät für Biologie, Ruhr-Universität, Bochum, Germany.
Neuroscience. 1999;92(4):1243-59. doi: 10.1016/s0306-4522(99)00009-3.
The physiological and morphological properties of interneurons in infragranular layers of rat visual cortex have been studied in organotypic cortex monocultures and thalamus-cortex co-cultures using intracellular recordings and biocytin injections. Cultures were prepared at the day of birth and maintained for up to 20 weeks. Twenty-nine interneurons of different types were characterized, in addition to 170 pyramidal neurons. The cultures developed a considerable degree of synaptically driven "spontaneous" bioelectric activity without epileptiform activity. Interneurons in cortex monocultures and thalamus-cortex co-cultures had the same physiological and morphological properties, and also pyramidal cell properties were not different in the two culture conditions. All interneurons and the majority of pyramidal cells displayed synaptically driven action potentials. The physiological group of fast-spiking interneurons included large basket cells, columnar basket cells (two cells with an arcade axon) and horizontally bitufted cells. The physiological group of slow-spiking interneurons included Martinotti cells and a "long-axon" cell. Analyses of the temporal patterns of activity revealed that fast-spiking interneurons have higher rates of spontaneous activity than slow-spiking interneurons and pyramidal cells. Furthermore, fast-spiking interneurons fired spontaneous bursts of action potentials in the gamma frequency range. We conclude from these findings that physiological and morphological properties of interneurons in organotypic mono- and co-cultures match those of interneurons characterized in vivo or in acute slice preparations, and they maintain in long-term cultures a well-balanced state of excitation and inhibition. This suggests that cortex-intrinsic or cell-autonomous mechanisms are sufficient for the expression of cell type-specific electrophysiological properties in the absence of afferents or sensory input.
利用细胞内记录和生物胞素注射技术，在器官型皮质单培养物和丘脑 - 皮质共培养物中研究了大鼠视觉皮质颗粒下层中间神经元的生理和形态特性。培养物在出生当天制备，并维持长达20周。除了170个锥体神经元外，还对29个不同类型的中间神经元进行了表征。培养物发展出了相当程度的由突触驱动的“自发”生物电活动，且无癫痫样活动。皮质单培养物和丘脑 - 皮质共培养物中的中间神经元具有相同的生理和形态特性，并且在两种培养条件下锥体细胞的特性也没有差异。所有中间神经元和大多数锥体细胞都表现出由突触驱动的动作电位。快速发放中间神经元的生理组包括大篮状细胞、柱状篮状细胞（两个具有弓状轴突的细胞）和水平双簇状细胞。慢速发放中间神经元的生理组包括马丁诺蒂细胞和一个“长轴突”细胞。对活动时间模式的分析表明，快速发放中间神经元的自发活动速率高于慢速发放中间神经元和锥体细胞。此外，快速发放中间神经元在γ频率范围内发放动作电位的自发爆发。我们从这些发现中得出结论，器官型单培养物和共培养物中中间神经元的生理和形态特性与体内或急性脑片制备中所表征的中间神经元的特性相匹配，并且它们在长期培养中维持了兴奋和抑制的良好平衡状态。这表明在没有传入神经或感觉输入的情况下，皮质内在或细胞自主机制足以表达细胞类型特异性的电生理特性。
