Comparative molecular biological studies on the vasoactive peptide receptors.

为了进一步了解血管活性肽的生理意义，我们对其受体进行了以下比较分子生物学研究。1)利钠肽受体：采用蛋白质测序和定点诱变相结合的方法，确定了牛和鳗鱼利钠肽受体C （NPR-C）亚基内和亚基间的二硫键模式。对哺乳动物NPR-C的cDNA和基因结构的分析显示，存在一个选择性剪接的mRNA物种，该物种在细胞外区域的近膜区编码一个序列略有修改的受体蛋白。一种新的受体亚型，称为NPR-D，已被鉴定、克隆和表征。NPR-D的细胞质尾部较短，与NPR-C序列相似70%，但在组织分布上有较大差异；大脑中含有大量的NPR-D。2)内皮素受体：免疫组化检测内皮素受体B （ET-B）的定位，发现血管内皮装饰最密集。A型内皮素受体（ET-A）在大鼠软骨膜和鳟鱼鳃上皮中高表达，提示内皮素参与软骨细胞的分化和鳃功能的调节。

To further advance our understanding on the physiological significance of vasoactive peptides, we carried out the following comparative molecular biological studies on their receptors.1) Natriuretic peptide receptors : The intra-and inter-subunit disulfide bonding pattern of the bovine and eel natriuretic peptide receptor C (NPR-C) were determined by a combination of protein sequencing and site-directed mutagenesis. Analysis of the cDNA and gene structures of mammalian NPR-C revealed the presence of an alternatively spliced mRNA species that encodes a receptor protein with a slightly modified sequence in the juxta-membrane region of the extracellular domain. A new receptor subtype, termed NPR-D,has been identified, cloned, and characterized. NPR-D has a short cytoplasmic tail and is 70% similar to the NPR-C sequence, but quite different in the tissue distribution ; NPR-D is abundant in the brain.2)Endothelin receptors : Localization of the endothelin receptor B (ET-B) was determined by immunohistochemistry and the vascular endotherium was found to be decorated most densely. Type A endothelin receptor (ET-A) was found to be highly expressed in the perichondrium of rats and the gill epitherium of trout, suggesting that endothelin is involved in the differentiation of chondrocytes and regulation of gill functions.