DEVELOPMENTAL EXPRESSION OF ALPHA(7) NEURONAL NICOTINIC RECEPTOR MESSENGER-RNA IN RAT SENSORY CORTEX AND THALAMUS
DEVELOPMENTAL EXPRESSION OF ALPHA(7) NEURONAL NICOTINIC RECEPTOR MESSENGER-RNA IN RAT SENSORY CORTEX AND THALAMUS
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DOI：
10.1016/0306-4522(94)00623-d
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发表时间：
1995-07-01
期刊：
影响因子：
3.3
通讯作者：
LESLIE, FM
中科院分区：
文献类型：
--
作者：
BROIDE, RS;OCONNOR, LT;LESLIE, FM
α(7) 信使 RNA 表达的分布以发育中的大鼠皮层和丘脑为特征。新生儿和成人皮质的 Northern 印迹分析揭示了 5.7 kb 的单个信使 RNA 转录本。使用全长和短S-35标记的α(7)核糖核酸探针进行原位杂交，观察到在出生后早期发育过程中感觉皮层和丘脑内信使RNA的独特瞬时表达。早在胚胎第13天，α(7)转录物就在新皮质的心室区和早在胚胎第15天的丘脑神经上皮中就以低水平表达。在产前后期，皮质和丘脑的感觉和非感觉区域的信使 RNA 水平显着增加。中等到高水平的信使RNA一直维持到出生后第一周，随后下降到成年期。出生后第 7 天幼犬的丘脑前背核、背外侧核、腹后内侧核和腹后外侧丘脑核中的 α(7) 信使 RNA 表达显着高于成年大脑。背侧膝状体、腹侧外侧膝状体和内侧膝状体内信使RNA的表达并未显示出随年龄的显着降低。在发育中的皮层中，信使 RNA 的表达以独特的层状模式描绘了初级体感、听觉和视觉皮层，这种模式始终显着高于成人的浅层 VI。出生后第 7 天的压后皮质中也观察到比成人更高的表达水平。出生后第 7 天皮质的切向切片显示低水平的 α(7) 信使 RNA 表达，描绘了第四层的主要感觉区域，对应于乙酰胆碱酯酶标记的丘脑皮质传入神经。然而，这些感觉区域表现出更高水平的 α(7) 信使 RNA 表达，并且在第 VI 层中更清晰地定义，但不是通过乙酰胆碱酯酶染色。 发育中的丘脑皮质系统中 α(7) 信使 RNA 的分布与 α-金环蛇毒素结合位点的分布平行，表明该受体位于丘脑细胞及其皮质目标神经元上。 α(7) 神经元烟碱受体的这种短暂且独特的分布模式与丘脑皮质发育的主要阶段相一致，表明它可能在皮质回路的发育中发挥功能性作用。
The distribution of alpha(7) messenger RNA expression was characterized in developing rat cortex and thalamus. Northern blot analysis of neonatal and adult cortex revealed a single messenger RNA transcript of 5.7 kb. Using in situ hybridization with both full length and short S-35-labeled alpha(7) riboprobes, a distinct transient expression of messenger RNA within sensory cortex and thalamus, during early postnatal development, was observed. alpha(7) transcripts were expressed in low levels as early as embryonic day 13 in the ventricular zone of the neocortex, and as early as embryonic day 15 in the thalamic neuroepithelium. A marked increase in messenger RNA levels was observed during the late prenatal period in both sensory and non-sensory regions of the cortex and thalamus. Moderate to high levels of messenger RNA were maintained into the first postnatal week, followed by a decline into adulthood. alpha(7) messenger RNA expression was significantly higher in the anterodorsal, lateral dorsal, ventral posterior medial and ventral posterior lateral thalamic nuclei of postnatal day 7 pups than in adult brains. Expression of messenger RNA within dorsal lateral geniculate, ventral lateral geniculate and medial geniculate did not show a significant reduction with age. Within the developing cortex, messenger RNA expression delineated the primary somatosensory, auditory and visual cortices in a unique laminar pattern that was consistently and significantly higher than in the adult in superficial layer VI. Higher levels of expression were also observed in retrosplenial cortex at postnatal day 7 than in the adult. Tangential sections through postnatal day 7 cortex revealed low levels of alpha(7) messenger RNA expression delineating the primary sensory areas in layer IV, corresponding to acetylcholinesterase-labeled thalamocortical afferents. However, these sensory areas exhibited higher levels of alpha(7) messenger RNA expression and were more clearly defined in layer VI, but not by acetylcholinesterase staining.The distribution of alpha(7) messenger RNA within the developing thalamocortical system parallels the distribution of alpha-bungarotoxin binding sites and suggests that the receptor is localized on both thalamic cells and their cortical target neurons. This transient and distinct pattern of distribution of the alpha(7) neuronal nicotinic receptor, which coincides with the major phase of thalamocortical development, suggests that it may play a functional role in the development of cortical circuitry.