Muscarinic receptor transcript and protein density in hypertrophied and atrophied rat urinary bladder
Muscarinic receptor transcript and protein density in hypertrophied and atrophied rat urinary bladder
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DOI：
10.1002/nau.20180
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发表时间：
2006-01-01
影响因子：
2
通讯作者：
Ruggieri, MR
中科院分区：
文献类型：
--
作者：
Braverman, AS;Ruggieri, MR
目的：我们以前的研究表明，膀胱肥大使介导收缩的M-3受体亚型从M-3向M-2沿着M-2蛋白浓度的增加和M-3蛋白浓度的减少。我们定量了M-1至M-5受体的mRNA，以确定M-2和M-3蛋白水平的变化是否是由于转录的变化。研究方法：膀胱肥大由膀胱出口梗阻（BOO），主要盆神经节电灼术（DEN）和主要盆神经节去中心化（DEC）引起。膀胱萎缩由输尿管改道（DIV）引起。其他组包括去神经和转向（DEN-DIV），假手术（SHAM）和正常（NOR）对照组。使用多重核糖核酸酶保护试验（RPA）定量转录物，并通过免疫沉淀法测定受体蛋白密度。每单位总RNA表达受体转录物。结果如下：尽管在所有实验组中检测到所有五种受体亚型转录物，但M-1、M-4和M-5的密度远低于M-2和M-3亚型。有更多的M-2受体转录比所有其他的，与M-2蛋白测定一致。M-2转录本在DEN和BOO膀胱中显著增加。令人惊讶的是，M-3转录物在BOO中也显著增加。在不同实验组中，M受体的蛋白密度与转录本密度之间存在显著相关性（r = 0.98，P < 0.001），而M-3受体的蛋白密度与转录本密度之间不存在相关性。结论：mRNA浓度的变化反映了M-3受体蛋白密度的变化，但不是M-3受体。从转录本密度数据外推功能效应对于M-3介导的膀胱收缩是无效的。
Aims: Our previous studies showed that bladder hypertrophy shifts the muscarinic receptor subtype mediating contraction from M-3 towards M-2 along with increased M-2 and decreased M-3 protein concentration. We quantified mRNA for M-1 through M-5 receptors to determine whether the changes in M-2 and M-3 protein levels was due to changes in transcription. Methods: Bladder hypertrophy was induced by bladder outlet obstruction (BOO), major pelvic ganglion electrocautery (DEN), and major pelvic ganglion decentralization (DEC). Bladder atrophy was induced by ureteral diversion (DIV). Additional groups included denervated and diverted (DEN-DIV), sham operated (SHAM), and normal (NOR) controls. Transcripts were quantified using a multiplex ribonuclease protection assay (RPA) and receptor protein density was determined by immuno-precipitation. Receptor transcripts were expressed per unit total RNA. Results: Although all five receptor subtype transcripts were detected in all experimental groups, the densities of M-1, M-4, and M-5 were much lower than for the M-2 and M-3 subtype. There were more M-2 receptor transcripts than all the others, consistent with M-2 protein determinations. M-2 transcripts were significantly increased in DEN and BOO bladders. Surprisingly, M-3 transcripts were also significantly increased in BOO. There was a significant correlation (r = 0.98, P < 0.001) between protein density and transcript density for the M, but not the M-3 receptor among the different experimental groups. Conclusions: Changes in mRNA concentration are reflected by changes in protein density for the M-3 receptor but not for the M-3 receptor. Extrapolation of functional effects from transcript density data is invalid for M-3 mediated bladder contractions.