α7 but not α4 AChR subunit expression is regulated by light in developing primary visual cortex
α7 but not α4 AChR subunit expression is regulated by light in developing primary visual cortex
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DOI：
10.1002/cne.20358
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发表时间：
2004-12-20
影响因子：
2.5
通讯作者：
Domenici, L
中科院分区：
文献类型：
--
作者：
Aztiria, E;Gotti, C;Domenici, L
在本文中，我们分析了α 4和α 7烟碱乙酰胆碱受体（nAChR）亚基在大鼠出生后发育的视觉皮层的表达模式，以澄清他们的表达是否发育调节和最终的发展变化是否调节视觉经验。我们发现，α 4和α 7 mRNA水平从出生后第12天（P12）睁眼前积累到P35左右。免疫组化结果表明，这两种亚基在除第I层外的所有皮质层均有表达。α 4亚单位免疫组化显示睁眼后第V层和第VI层中阳性细胞数量显著增加。在α 7亚基的情况下，免疫反应细胞的数量增加，在所有皮层层后不久，眼睛打开，除了在第VI层，匹配的结果发现在转录水平。在黑暗中饲养的动物从P9到P22，α 4 mRNA的相对量和免疫反应细胞的数量没有表现出变化。H-3-epibatidine结合实验表明，异聚nAChR亚单位的数量在黑暗饲养大鼠没有改变相对于年龄匹配的控制，从而证实了免疫组化结果。α 7亚基的mRNA在黑暗饲养的大鼠中保持稳定，而免疫反应细胞的数量和分布发生变化。此外，在黑暗饲养的动物中，I-125 alphabungarotoxin结合nAChRs的数量显著增加。这些结果表明，视觉输入的视觉皮层刺激是一个重要的步骤，为α 7 nAChR正常表达，这表明这些受体在经验依赖的方式对这个皮层区域的成熟可能发挥作用。(C)2004威利-利斯公司
In the present paper we analyzed the expression pattern of the alpha4 and alpha7 nicotinic acetylcholine receptor (nAChR) subunits in the rat visual cortex through postnatal development, to clarify whether their expression is developmentally regulated and whether eventual developmental changes are regulated by visual experience. We found that both alpha4 and alpha7 mRNA levels accumulate from postnatal day 12 (P12) before eye opening, to around P35. The immunohistochemical results indicated that both subunits are expressed throughout all cortical laminae, except layer I. alpha4 subunit immunohistochemistry revealed significant increments in the number of positive cells in layers V and VI after eye opening. In the case of the alpha7 subunit, the number of immunoreactive cells increased in all cortical layers soon after eye opening, except in layer VI, matching the results found at the transcriptional level. In animals reared in darkness from P9 to P22, the relative amount of the alpha4 mRNA and the number of immunoreactive cells exhibited no changes. H-3-epibatidine binding experiments showed that the number of heteromeric nAChR subunitsin dark-reared rats did not change with respect to age-matched controls, thus confirming the immunohistochemical results. The mRNA of the alpha7 subunit remained stable in dark-reared rats, whereas the number and distribution of immunoreactive cells changed. Moreover, the number of I-125 alphabungarotoxin-binding nAChRs was significantly increased in dark-reared animals. These results indicate that visual cortex stimulation by visual input is an essential step for alpha7 nAChR normal expression, suggesting a possible role for these receptors in an experience-dependent fashion on the maturation of this cortical area. (C) 2004 Wiley-Liss, Inc.