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Regulation of uterine GABA_A receptor subunit expression throughout pregnancy

整个妊娠期子宫 GABA_A 受体亚基表达的调节

基本信息

批准号：
12671597
负责人：
FUJII Eriko
金额：
$ 1.02万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12671597/
关键词：
allopregnanolone GABA_A π subunit myometrium partuition π subunit GABA_A receptor subunit 妊娠子宮 steroid hormone

项目摘要

[OBJECTIVE] A new subunit of GABA_A receptor, named it, is abundant only in the uterus. Since allopregnanolone works through the GABA_A receptor and reduce uterine contraction, α subunit might change the sensitivity of GABA_A receptor to allopregnanolone and modulate the parturition. The purpose of this study was to determine the expressions of GABA_A receptor subunits in the uteri from various gestational ages, especially for the n subunit, and examine the correlation between the combination of the subunits and physiological properties.[METHODS] Uterine tissues from the timed pregnant rats (13.5 - 21.5 gestational days), non-pregnant proven breeders and postpartum day-1 rats were used to obtain plasma membranes and RNAs. Following RT-PCR and subcloning, RNase protection assay was performed to determine the mRNA expressions of GABA_A receptor π subunit and 3 HSD throughout the pregnancy. We also examined the expressions of the other GABA_A receptor subunits in the rat uteri throughout … More the pregnancy by semi-quantitative PCR. Then we performed ^3H-muscimol binding assay to the GABA_A receptor on the plasma membranes in various gestational uteri and examined the difference of the effect of allopregnanolone on the binding.[RESULTS] The expression of GABA_A π subunit mRNA was decreased at onset of labor, and 3αHSD mRNA were decreased on postpartum day-1. Semi-quantitative PCR study showed that GABA_Aα1 subunit expression was increased, while α2 and α subunits expressions were decreased during the pregnancy, and α3 subunit only appeared on postpartum day-1. GABA_A receptor in non-pregnant uterus appeared to have the high affinity binding site (Kd=1.79nM, Bmax=4.9pmole/mg protein) and the low affinity binding site (Kd=52.6nM, Bmax=12.1pmole/ mg protein) to ^3H-muscimol. And the results of the binding assay showed that the GABA_A receptor in uteri was most sensitive to allopregnanolone on 19.5 days gestation and was least sensitive in labor.[CONCLUSION] We detected that the subunits combinations of the GABA_A receptor are different in the uteri from various gestational days. The function of the each combination of the subunits is still unclear. However it was suggested that the difference of GABA_A receptor subunit expression during pregnancy may change the sensitivity of GABA_A receptor to allopregnanolone and have a regulating effect on the parturition. Less

[目的] GABA_A受体的一个新的亚单位，仅在子宫中存在。由于别孕烯醇酮通过GABA_A受体发挥作用，减弱子宫收缩，α亚单位可能通过改变GABA_A受体对别孕烯醇酮的敏感性，从而调节分娩。本研究的目的是测定不同胎龄子宫中GABA_A受体亚单位的表达，特别是n亚单位的表达，并探讨其亚单位组合与生理特性的相关性。[方法]取定时妊娠大鼠（妊娠13.5 ~ 21.5 d）、非妊娠成熟种鼠和产后1 d大鼠子宫组织，提取质膜和RNA。RT-PCR和亚克隆技术后，采用RNase保护试验检测妊娠期GABAA受体π亚基和3-HSD mRNA的表达。我们还检测了其他GABA_A受体亚单位在大鼠子宫中的表达， ...更多信息半定量PCR检测妊娠。然后用^3H-蝇蕈醇结合法测定了不同妊娠子宫内膜GABA_A受体的结合率，并观察了别孕烯醇酮对结合率影响的差异。[结果]分娩开始时GABA_A π亚基mRNA表达下降，产后第1天3αHSD mRNA表达下降。半定量PCR结果显示，妊娠期GABA_Aα1亚基表达增加，α2和α亚基表达减少，α3亚基仅在产后第1天出现。非妊娠子宫中GABA_A受体对^3H-蝇蕈醇有高亲和力结合位点（Kd= 1.79 nM，Bmax= 4.9 pmole/mg蛋白）和低亲和力结合位点（Kd= 52.6 nM，Bmax= 12.1 pmole/ mg蛋白）。结合试验结果表明，子宫GABA_A受体在妊娠19.5天对别孕烯醇酮最敏感，分娩期最不敏感。[结论]不同孕周子宫内GABA_A受体亚基组合存在差异。每个亚基组合的功能尚不清楚。提示妊娠期GABA_A受体亚单位表达的差异可能改变了GABA_A受体对别孕烯醇酮的敏感性，从而对分娩有调节作用。少