Fu M, Ji X, Zhong L, Wu Q, Li H, Wang N
Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China.
Department of Quality Management, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China.
Nan Fang Yi Ke Da Xue Xue Bao. 2023 Jul 20;43(7):1102-1109. doi: 10.12122/j.issn.1673-4254.2023.07.06.
To investigate the variations in the expression of voltage-gated sodium (Na) channel subunits during development of rat cerebellar Purkinje neurons and their correlation with maturation of electrophysiological characteristics of the neurons.
We observed the changes in the expression levels of Na1.1, 1.2, 1.3 and 1.6 during the development of Purkinje neurons using immunohistochemistry in neonatal (5-7 days after birth), juvenile (12-14 days), adolescent (21-24 days), and adult (42-60 days) SD rats. Using whole-cell patch-clamp technique, we recorded the spontaneous electrical activity of the neurons in ex vivo brain slices of rats of different ages to analyze the changes of electrophysiological characteristics of these neurons during development.
The expression of Na subunits in rat cerebellar Purkinje neurons showed significant variations during development. Na1.1 subunit was highly expressed throughout the developmental stages and increased progressively with age ( < 0.05). Na1.2 expression was not detected in the neurons in any of the developmental stages ( > 0.05). The expression level of Na1.3 decreased with development and became undetectable after adolescence ( < 0.05). Na1.6 expression was not detected during infancy, but increased with further development ( < 0.05). Na1.1 and Na1.3 were mainly expressed in the early stages of development. With the maturation of the rats, Na1.3 expression disappeared and Na1.6 expression increased in the neurons. Na1.1 and Na1.6 were mainly expressed after adolescence. The total Na protein level increased gradually with development ( < 0.05) and tended to stabilize after adolescence. The spontaneous frequency and excitability of the Purkinje neurons increased gradually with development and reached the mature levels in adolescence. The developmental expression of Na subunits was positively correlated with discharge frequency (=0.9942, < 0.05) and negatively correlated with the excitatory threshold of the neurons (=0.9891, < 0.05).
The changes in the expression levels of Na subunits are correlated with the maturation of high frequency electrophysiological properties of the neurons, suggesting thatmature Na subunit expressions is the basis of maturation of electrophysiological characteristics of the neurons.
研究大鼠小脑浦肯野神经元发育过程中电压门控钠（Na）通道亚单位表达的变化及其与神经元电生理特性成熟的相关性。
采用免疫组织化学方法观察新生（出生后5 - 7天）、幼年（12 - 14天）、青春期（21 - 24天）和成年（42 - 60天）SD大鼠浦肯野神经元发育过程中Na1.1、1.2、1.3和1.6表达水平的变化。使用全细胞膜片钳技术，记录不同年龄大鼠离体脑片神经元的自发放电活动，分析这些神经元发育过程中电生理特性的变化。
大鼠小脑浦肯野神经元中Na亚单位的表达在发育过程中呈现显著变化。Na1.1亚单位在整个发育阶段均高表达且随年龄逐渐增加（<0.05）。在任何发育阶段的神经元中均未检测到Na1.2的表达（>0.05）。Na1.3的表达水平随发育降低，青春期后不可检测（<0.05）。在婴儿期未检测到Na1.6的表达，但随进一步发育而增加（<0.05）。Na1.1和Na1.3主要在发育早期表达。随着大鼠成熟，神经元中Na1.3表达消失而Na1.6表达增加。Na1.1和Na1.6主要在青春期后表达。总Na蛋白水平随发育逐渐增加（<0.05），青春期后趋于稳定。浦肯野神经元的自发频率和兴奋性随发育逐渐增加，在青春期达到成熟水平。Na亚单位的发育表达与放电频率呈正相关（=0.9942，<0.05），与神经元的兴奋阈值呈负相关（=0.9891，<0.05）。
Na亚单位表达水平的变化与神经元高频电生理特性的成熟相关，提示成熟的Na亚单位表达是神经元电生理特性成熟的基础。
