Regulation of perinatal respiration-related activity and Cl- homeostasis : searching for the factors of sudden infant death syndrome in the brain

阳离子-氯离子共转运蛋白被认为在调节细胞内氯离子浓度（[Cl^-] i），进而控制神经元功能中起着关键作用。首先，我用KCC 2抗体检测了发育中的小鼠延髓中KCC 2的免疫反应性。舌下神经核KCC 2免疫反应性P0时高于P7时，而迷走神经核KCC 2免疫反应性P0时无明显变化。由于发育变化的KCC 2表达模式与呼吸相关的节律活动（RRA）在髓质尚未得到很好的理解，我记录RRA细胞外呼吸相关的神经元在髓质切片制备从小鼠的P0-7。在这些条件下，灌注100μM含GABA的ACSF可短暂增加RRA的频率。KCC 2抑制剂呋塞米也增加了RRA的频率。因此，Cl^-稳态可能在出生后早期调节运动输出活动。

Cation-chloride cotransporters are considered to play critical roles in the regulation of intracellular chloride ion concentration ([Cl^-]_i), and hence in the control of neuronal function. First, I tested the immunoreactivity of KCC2 using KCC2 antibody in developmental mouse medulla. Immunoreactivity of KCC2 in hypoglossal nucleus at P0 was higher than that at P7, while that of vagus nerve nucleus did not change during same period. Since developmental changes in expression pattern of KCC2 associated with respiration-related rhythmic activity (RRA) in medulla are not yet well understood, I recorded RRA extracellulary from respiration-related neurons in medullary slice preparation obtained from mice of P0-7. Under these conditions, perfusion of 100μM GABA-containing ACSF transiently increased the frequency of RRA. The KCC2 inhibitor furosemide also increased the frequency of RRA. Thus Cl^- homeostasis likely regulates the activity of motor output in early postnatal stage.