Developmental regulation of the membrane properties of central vestibular neurons by sensory vestibular information in the mouse
Developmental regulation of the membrane properties of central vestibular neurons by sensory vestibular information in the mouse
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DOI：
10.1113/jphysiol.2007.133710
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发表时间：
2007-09-15
影响因子：
5.5
通讯作者：
Vibert, N.
中科院分区：
文献类型：
--
作者：
Eugene, D.;Deforges, S.;Vibert, N.
使用一种转基因、前庭缺陷突变型KCNE 1（-/-）小鼠研究了前庭输入缺乏对中枢前庭神经元膜特性的影响，该小鼠出生后内耳毛细胞立即退化。尽管没有感觉前庭输入，他们的中央前庭通路是完整的。青少年和成年纯合子突变体有一个正常的休息姿势，但表现出一个恒定的头部摆动行为，并显示shaker/waltzer表型，其特征是在运动过程中快速双边盘旋。在幼年小鼠中，KCNE 1突变与前庭内侧核（MVN）内钙结合蛋白、钙视黄蛋白和小白蛋白表达的强烈下降以及MVN神经元膜特性的重要改变相关。然而，在成年小鼠中，纯合子和对照或杂合子突变小鼠的MVN神经元的膜特性之间几乎没有差异，这些小鼠具有正常的内耳毛细胞并且没有表现出行为症状。钙结合蛋白和钙视网膜蛋白的表达水平较低的成年纯合子突变动物，但在MVN中表达的钙结合蛋白的量是远远大于在幼年小鼠。这些数据表明，在出生前后的“敏感期”内抑制感觉前庭输入可以产生盘旋/华尔兹行为，但这种行为不是由于中枢前庭神经元膜特性的持续异常。总而言之，中枢前庭神经元膜特性的成熟被延迟，但不因感觉前庭信息的缺乏而受损。
The effect of the lack of vestibular input on the membrane properties of central vestibular neurons was studied by using a strain of transgenic, vestibular-deficient mutant KCNE 1(-/-) mice where the hair cells of the inner ear degenerate just after birth. Despite the absence of sensory vestibular input, their central vestibular pathways are intact. Juvenile and adult homozygous mutant have a normal resting posture, but show a constant head bobbing behaviour and display the shaker/waltzer phenotype characterized by rapid bilateral circling during locomotion. In juvenile mice, the KCNE1 mutation was associated with a strong decrease in the expression of the calcium-binding proteins calbindin, calretinin and parvalbumin within the medial vestibular nucleus (MVN) and important modifications of the membrane properties of MVN neurons. In adult mice, however, there was almost no difference between the membrane properties of MVN neurons of homozygous and control or heterozygous mutant mice, which have normal inner ear hair cells and show no behavioural symptoms. The expression levels of calbindin and calretinin were lower in adult homozygous mutant animals, but the amount of calcium-binding proteins expressed in the MVN was much greater than in juvenile mice. These data demonstrate that suppression of sensory vestibular inputs during a 'sensitive period' around birth can generate the circling/waltzing behaviour, but that this behaviour is not due to persistent abnormalities of the membrane properties of central vestibular neurons. Altogether, maturation of the membrane properties of central vestibular neurons is delayed, but not impaired by the absence of sensory vestibular information.