Development of K+ and Na+ conductances in rodent postnatal semicircular canal type I hair cells
Development of K+ and Na+ conductances in rodent postnatal semicircular canal type I hair cells
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DOI：
10.1152/ajpregu.00460.2009
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发表时间：
2010-02-01
影响因子：
2.8
通讯作者：
Rennie, Katherine J.
中科院分区：
文献类型：
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作者：
Li, Gang Q.;Meredith, Frances L.;Rennie, Katherine J.
李国强，梅雷迪思FL，Rennie KJ.啮齿动物出生后半规管I型毛细胞K+和Na+电导的发育。Am J Physiol Regul Integr Comp Physiol 298：R351-R358，2010年。首次发表于2009年11月25日; doi：10.1152/ajpregu.00460.2009。啮齿动物的前庭系统在出生时是不成熟的。在出生后的第一周，前庭I型和II型毛细胞开始获得其特征性的形态和传入神经支配。我们已经研究了出生后的变化，I型毛细胞的膜特性急性分离的半规管（SCC）的沙鼠和大鼠使用全细胞膜片钳和报告的第一次在这些细胞中的离子电导的发展变化。在出生后第5天（P），两种动物的未成熟毛细胞表达延迟整流钾离子传导（G（DR）），其在约-50 mV以上的电位下激活。毛细胞还表达了瞬时Na+电导（G（Na）），平均半失活约为-90 mV。在大鼠P6和沙鼠P7，首次观察到低电压激活的K+电导（G（K，L）），并赋予SCC I型毛细胞低输入电阻，典型的成年I型毛细胞。G（K，L）在毛细胞中的表达显着增加，在出生后第二周，并存在于所有大鼠I型毛细胞的P14。在沙鼠毛细胞中，G（K，L）出现较晚，到P19时已存在于所有I型毛细胞中。在出生后第3周，G（Na）的表达下降，并在出生后第4周的大鼠和沙鼠出生后第6周的缺席。了解与毛细胞成熟相关的离子变化有助于阐明内耳的发育和再生机制。
Li GQ, Meredith FL, Rennie KJ. Development of K+ and Na+ conductances in rodent postnatal semicircular canal type I hair cells. Am J Physiol Regul Integr Comp Physiol 298: R351-R358, 2010. First published November 25, 2009; doi:10.1152/ajpregu.00460.2009.-The rodent vestibular system is immature at birth. During the first postnatal week, vestibular type I and type II hair cells start to acquire their characteristic morphology and afferent innervation. We have studied postnatal changes in the membrane properties of type I hair cells acutely isolated from the semicircular canals (SCC) of gerbils and rats using whole cell patch clamp and report for the first time developmental changes in ionic conductances in these cells. At postnatal day (P) 5 immature hair cells expressed a delayed rectifier K+ conductance (G(DR)) which activated at potentials above approximately -50 mV in both species. Hair cells also expressed a transient Na+ conductance (G(Na)) with a mean half-inactivation of approximately -90 mV. At P6 in rat and P7 in gerbil, a low-voltage activated K+ conductance (G(K,L)) was first observed and conferred a low-input resistance, typical of adult type I hair cells, on SCC type I hair cells. G(K,L) expression in hair cells increased markedly during the second postnatal week and was present in all rat type I hair cells by P14. In gerbil hair cells, G(K,L) appeared later and was present in all type I hair cells by P19. During the third postnatal week, G(Na) expression declined and was absent by the fourth postnatal week in rat and the sixth postnatal week in gerbils. Understanding the ionic changes associated with hair cell maturation could help elucidate development and regeneration mechanisms in the inner ear.