Changes in gamma-aminobutyrate type A receptor subunit mRNAs, translation product expression, and receptor function during neuronal maturation in vitro.
Changes in gamma-aminobutyrate type A receptor subunit mRNAs, translation product expression, and receptor function during neuronal maturation in vitro.
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体外神经元成熟过程中 γ-氨基丁酸 A 型受体亚基 mRNA、翻译产物表达和受体功能的变化。
DOI：
10.1073/pnas.91.23.10952
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发表时间：
1994
影响因子：
11.1
通讯作者：
Caruncho,HJ
中科院分区：
文献类型：
--
作者：
Zheng,TM;Zhu,WJ;Puia,G;Vicini,S;Grayson,DR;Costa,E;Caruncho,HJ
在原代培养的新生大鼠颗粒细胞生长过程中，监测编码γ-氨基丁酸A型（GABAA）受体α 1，α 6，β 2，β 3，γ 2和δ亚基的mRNA的量及其翻译产物的金免疫标记密度。我们研究了可能的相关性（i）mRNA含量的时间变化和各自翻译产物的表达密度之间的相关性，以及（ii）受体亚基表达的定量变化、GABA对Cl-通道激活的EC 50和地西泮调节GABA对Cl-通道作用的效力之间的相关性。在体外3天时，GABAA受体亚基mRNA的量及其各自的翻译产物的表达非常低。在接下来的2周内，研究的每个亚基的两个参数均异步增加;此外，在体外14天时，γ 2和δ亚基表达的总和小于α 1或α 6或β 2/β 3亚基的表达。这表明，在体外成熟过程中，每个亚基可以独立地调节，并邀请推测在体外发育过程中特定GABAA受体亚型丰度的可能变化。GABA引起的最大电流强度在体外培养5 ~ 14天没有增加，但编码各亚基的mRNA的量和各自翻译产物的表达密度增加。因此，在GABAA受体亚型表达和/或异常的亚基组装的定性变化很可能占GABA在体外开发过程中引起的最大电流强度的均匀性。此外，在成熟的神经元培养物从5至20天在体外的GABA作用的地西泮的积极调制的程度显着下降。这一发现可能与GABAA受体（包括α 6亚基）丰度的增加和/或与颗粒细胞体外成熟过程中缺乏γ 2亚基的GABAA受体的表达有关。
The amounts of mRNAs encoding alpha 1, alpha 6, beta 2, beta 3, gamma 2, and delta subunits of gamma-aminobutyrate type A (GABAA) receptors and the gold immunolabeling density of their translation products were monitored during the growth of neonatal rat granule cells in primary culture. We investigated possible correlations (i) between temporal changes in mRNA content and expression density of their respective translation products and (ii) between the quantitative changes of receptor subunit expression, the GABA EC50 for Cl- channel activation, and diazepam efficacy in modulating GABA action on the Cl- channels. At 3 days in vitro, the amount of GABAA receptor subunit mRNAs and the expression of their respective translation products were very low. During the next 2 weeks both parameters for every subunit studied increased asynchronously; moreover, at 14 days in vitro the sum of gamma 2 and delta subunit expression was smaller than the expression of the alpha 1 or alpha 6 or beta 2/beta 3 subunits. This suggests that during in vitro maturation each subunit may be regulated independently and invites speculation as to possible changes in specific GABAA receptor subtype abundance during development in vitro. The maximal current intensity elicited by GABA failed to increase from 5 to 14 days in vitro, though the amount of mRNA encoding various subunits and the expression density of their respective translation products increased. Thus, qualitative changes in the GABAA receptor subtypes expressed and/or abnormalities in the subunit assembly very likely account for the uniformity of the maximal current intensity elicited by GABA during in vitro development. Also, during maturation of neuronal cultures from 5 to 20 days in vitro the extent of the positive modulation of GABA action by diazepam decreased dramatically. This finding might be related to an increase in the abundance of GABAA receptors including the alpha 6 subunit and/or to the expression, during granule cell maturation in vitro, of GABAA receptors devoid of gamma 2 subunits.