Rokosh D G, Bailey B A, Stewart A F, Karns L R, Long C S, Simpson P C
Division of Cardiology, Veterans Affairs Medical Center, San Francisco, California 94121.
Biochem Biophys Res Commun. 1994 May 16;200(3):1177-84. doi: 10.1006/bbrc.1994.1575.
Two alpha 1-adrenergic receptor (AR) subtypes have been defined by pharmacological studies in rat tissues, the alpha 1A and the alpha 1B, whereas three alpha 1-ARs have been cloned, alpha 1B, alpha 1C, and alpha 1D. It has been reported that alpha 1C mRNA is absent in all rat tissues, making uncertain the correspondence of this cloned subtype, if any, to the native alpha 1-ARs defined by pharmacological criteria. In the present study, a partial alpha 1C-AR cDNA was obtained from rat cardiac myocytes using RT-PCR with degenerate primers. A sensitive RNase protection assay was used to map the distribution of alpha 1C mRNA in adult rat tissues, in comparison with alpha 1B and alpha 1D. alpha 1C mRNA was abundant in heart, brain, aorta, vena cava, vas deferens, submaxillary gland, lung, and kidney; was detected at lower levels in prostate, parotid gland, and skeletal muscle; and was undetectable in liver and spleen. alpha 1B and alpha 1D mRNAs were present in most of the same tissues. In contrast to alpha 1C, however, alpha 1B and alpha 1D were both present in spleen; alpha 1B was the sole alpha 1-AR mRNA in liver; and alpha 1D mRNA was not detected in submaxillary gland, a tissue known to be enriched in the pharmacological alpha 1A. We conclude that the distribution of alpha 1C-AR mRNA in rat tissues is compatible with the idea that the alpha 1C corresponds to the classical native alpha 1A-AR. Although many tissues contain all three alpha 1-AR mRNAs, distinct tissue-specific expression is evident.
通过对大鼠组织的药理学研究已确定了两种α1 - 肾上腺素能受体（AR）亚型，即α1A和α1B，而现已克隆出三种α1 - AR，即α1B、α1C和α1D。据报道，在所有大鼠组织中均不存在α1C mRNA，因此这种克隆亚型（如果有的话）与根据药理学标准定义的天然α1 - AR之间的对应关系尚不确定。在本研究中，使用简并引物通过逆转录聚合酶链反应（RT - PCR）从大鼠心肌细胞中获得了部分α1C - AR cDNA。与α1B和α1D相比，采用灵敏的核糖核酸酶保护试验来绘制α1C mRNA在成年大鼠组织中的分布图。α1C mRNA在心脏、脑、主动脉、腔静脉、输精管、颌下腺、肺和肾中含量丰富；在前列腺、腮腺和骨骼肌中检测到的水平较低；在肝脏和脾脏中未检测到。α1B和α1D mRNA存在于大多数相同的组织中。然而，与α1C不同的是，α1B和α1D在脾脏中均存在；α1B是肝脏中唯一的α1 - AR mRNA；在颌下腺（已知在药理学上富含α1A的组织）中未检测到α1D mRNA。我们得出结论，α1C - AR mRNA在大鼠组织中的分布与α1C对应于经典天然α1A - AR的观点相符。尽管许多组织都含有所有三种α1 - AR mRNA，但明显存在不同的组织特异性表达。
