Gerald C, Adham N, Kao H T, Olsen M A, Laz T M, Schechter L E, Bard J A, Vaysse P J, Hartig P R, Branchek T A
Synaptic Pharmaceutical Corporation, Paramus, NJ 07652, USA.
EMBO J. 1995 Jun 15;14(12):2806-15. doi: 10.1002/j.1460-2075.1995.tb07280.x.
Molecular cloning efforts have provided primary amino acid sequence and signal transduction data for a large collection of serotonin receptor subtypes. These include five 5-HT1-like receptors, three 5-HT2 receptors, one 5-HT3 receptor, two 5-HT5 receptors, one 5-HT6 receptor and one 5-HT7 receptor. Molecular biological information on the 5-HT4 receptor is notably absent from this list. We now report the cloning of the pharmacologically defined 5-HT4 receptor. Using degenerate oligonucleotide primers, we identified a rat brain PCR fragment which encoded a '5-HT receptor-like' amino acid sequence. The corresponding full length cDNA was isolated from a rat brain cDNA library. Transiently expressed in COS-7 cells, this receptor stimulates adenylyl cyclase activity and is sensitive to the benzamide derivative cisapride. The response is also blocked by ICS-205930. Interestingly, we isolated two splice variants of the receptor, 5-HT4L and 5-HT4S, differing in the length and sequence of their C-termini. In rat brain, the 5-HT4S transcripts are restricted to the striatum, but the 5-HT4L transcripts are expressed throughout the brain, except in the cerebellum where it was barely detectable. In peripheral tissues, differential expression was also observed in the atrium of the heart where only the 5-HT4S isoform was detectable.
分子克隆研究已为大量血清素受体亚型提供了一级氨基酸序列和信号转导数据。这些亚型包括五个5-HT1样受体、三个5-HT2受体、一个5-HT3受体、两个5-HT5受体、一个5-HT6受体和一个5-HT7受体。而5-HT4受体的分子生物学信息在这份清单中明显缺失。我们现在报告药理学上定义的5-HT4受体的克隆情况。使用简并寡核苷酸引物，我们鉴定出一个大鼠脑PCR片段，其编码一个“血清素受体样”氨基酸序列。从大鼠脑cDNA文库中分离出相应的全长cDNA。该受体在COS-7细胞中瞬时表达时，可刺激腺苷酸环化酶活性，并且对苯甲酰胺衍生物西沙必利敏感。该反应也被ICS-205930阻断。有趣的是，我们分离出该受体的两种剪接变体，5-HT4L和5-HT4S，它们的C末端长度和序列不同。在大鼠脑中，5-HT4S转录本仅限于纹状体，但5-HT4L转录本在整个大脑中均有表达，除了在小脑几乎检测不到。在周围组织中，在心脏心房也观察到差异表达，其中仅可检测到5-HT4S亚型。
