Erlinge D, Hou M, Webb T E, Barnard E A, Möller S
Department of Internal Medicine, Lund University Hospital, Sweden.
Biochem Biophys Res Commun. 1998 Jul 30;248(3):864-70. doi: 10.1006/bbrc.1998.9083.
Studies using selective agonists have suggested that the contractile effect of extracellular nucleotides, such as ATP and UTP, in blood vessels is mediated mainly by P2X1 receptors with a smaller contribution of P2Y receptors while the mitogenic effect is mediated by P2Y (P2Y1, P2Y2, P2Y4, and P2Y6) receptors with no effect of P2X1 receptors. This indicates a difference in P2 receptor expression between the contractile and the synthetic phenotype of the SMC. To measure the expression of mRNA for these receptors a competitive RT-PCR assay was developed that utilised synthetic RNA-competitors allowing determination of the number of mRNA copies for each receptor in the samples. In the synthetic phenotype the mitogenic P2Y1 and P2Y2 receptor transcripts were upregulated by 342- and 8-fold, respectively, while the contractile P2X1 receptor is totally downregulated and the P2Y4 and P2Y6 receptors were unchanged. This plasticity of the receptor expression may be important in the transition from the contractile to the synthetic SMC phenotype.
使用选择性激动剂的研究表明，细胞外核苷酸（如ATP和UTP）在血管中的收缩作用主要由P2X1受体介导，P2Y受体的作用较小，而促有丝分裂作用则由P2Y（P2Y1、P2Y2、P2Y4和P2Y6）受体介导，P2X1受体无作用。这表明平滑肌细胞收缩表型和合成表型之间P2受体表达存在差异。为了测量这些受体的mRNA表达，开发了一种竞争性RT-PCR检测方法，该方法利用合成RNA竞争物来确定样品中每个受体的mRNA拷贝数。在合成表型中，促有丝分裂的P2Y1和P2Y2受体转录本分别上调了342倍和8倍，而收缩性的P2X1受体完全下调，P2Y4和P2Y6受体则没有变化。这种受体表达的可塑性可能在收缩性平滑肌细胞表型向合成性表型的转变中起重要作用。
