Department of Otorhinolaryngology-Head & Neck Surgery, Chuncheon Sacred Hospital, Hallym University College of Medicine, Chuncheon 200-704, Korea.
Korean J Physiol Pharmacol. 2008 Jun;12(3):95-9. doi: 10.4196/kjpp.2008.12.3.95. Epub 2008 Jun 30.
Calcium (Ca(2+)) is an intracellular second messenger associated with neuronal plasticity of the central nervous system. The calcium-binding proteins regulate the Ca(2+)-mediated signals in the cytoplasm and buffer the calcium concentration. This study examined temporal changes of three calcium-binding proteins (calretinin, calbindin and parvalbumin) in the medial vestibular nucleus (MVN) during vestibular compensation after unilateral labyrinthectomy (UL) in rats. Rats underwent UL, and the changes in the expression of these proteins at 2, 6, 12, 24, 48, and 72 h were examined by immunofluorescence staining. The expression levels of all three proteins increased immediately after UL and returned to the control level by 48 h. However, the level of calretinin showed changes different from the other two proteins, being expressed at significantly higher level in the contralateral MVN than in the ipsilateral MVN 2 h after UL, whereas the other two proteins showed similar expression levels in both the ipsilateral and contralateral MVN. These results suggest that the calcium binding proteins have some protective activity against the increased Ca(2+) levels in the MVN. In particular, calretinin might be more responsive to neuronal activity than calbindin or parvalbumin.
钙（Ca(2+)) 是一种与中枢神经系统神经元可塑性相关的细胞内第二信使。钙结合蛋白调节细胞质中 Ca(2+)介导的信号，并缓冲钙离子浓度。本研究在大鼠单侧迷路切除（UL）后观察了内侧前庭核（MVN）中三种钙结合蛋白（钙调蛋白、钙结合蛋白和副甲状腺蛋白）在前庭代偿期间的时间变化。大鼠接受 UL 后，通过免疫荧光染色检测这些蛋白在 2、6、12、24、48 和 72 h 时的表达变化。三种蛋白的表达水平在 UL 后立即增加，并在 48 h 时恢复到对照水平。然而，钙调蛋白的水平表现出与其他两种蛋白不同的变化，在 UL 后 2 h 时，其在对侧 MVN 中的表达水平明显高于同侧 MVN，而其他两种蛋白在同侧和对侧 MVN 中的表达水平相似。这些结果表明，钙结合蛋白对 MVN 中 Ca(2+)水平的升高具有一定的保护作用。特别是钙调蛋白可能比钙结合蛋白或副甲状腺蛋白对神经元活动更敏感。
