Herrick-Davis K, Titeler M
Department of Pharmacology and Toxicology, Albany Medical College, New York 12208.
Synapse. 1989;3(4):325-30. doi: 10.1002/syn.890030405.
Radioligand binding studies were performed to characterize serotonin 5HT1D binding sites in porcine and bovine brain. 3H-5HT binding, in the presence of 1 microM (+/-)pindolol (to block 5HT1A and 5HT1B receptors) and 100 nM mesulergine (to block 5HT1C receptors), was specific, saturable, and of high affinity. In porcine and bovine cortex and striatum the majority of 5HT1 sites (80%-90%) were of the 5HT1D subtype. In competition experiments 8-OH-DPAT, TFMPP, mesulergine, DOB, and ICS 205-930 had low affinity for 3H-5HT-labeled 5HT1D sites, indicating that the pharmacology of the 5HT1D site is distinct from previously identified 5HT1A, 5HT1B, 5HT1C, 5HT2, and 5HT3 sites. Guanyl nucleotides, GTPgammaS, and Gpp(NH)p, and divalent cations potently modulated the binding of 3H-5HT to 5HT1D sites in porcine and bovine striatum. Mg++ ions increased the number and affinity of 3H-5HT-labeled 5HT1D sites, while guanyl nucleotides decreased the number of 3H-5HT-labeled 5HT1D sites. These results demonstrate the presence of the 5HT1D receptors in porcine striatum and bovine cortex and provide direct demonstration that the radioligand binding assay for the 5HT1D receptor can monitor the interaction of this receptor with a GTP-binding protein.
进行放射性配体结合研究以表征猪和牛脑中的5-羟色胺5HT1D结合位点。在存在1 microM（±）吲哚洛尔（以阻断5HT1A和5HT1B受体）和100 nM美舒麦角（以阻断5HT1C受体）的情况下，3H-5HT结合具有特异性、可饱和性且亲和力高。在猪和牛的皮质及纹状体中，大多数5HT1位点（80%-90%）属于5HT1D亚型。在竞争实验中，8-OH-DPAT、TFMPP、美舒麦角、DOB和ICS 205-930对3H-5HT标记的5HT1D位点亲和力较低，这表明5HT1D位点的药理学特性与先前鉴定的5HT1A、5HT1B、5HT1C、5HT2和5HT3位点不同。鸟苷酸、GTPγS和Gpp(NH)p以及二价阳离子强烈调节猪和牛纹状体中3H-5HT与5HT1D位点的结合。Mg++离子增加了3H-5HT标记的5HT1D位点的数量和亲和力，而鸟苷酸则减少了3H-5HT标记的5HT1D位点的数量。这些结果证明了猪纹状体和牛皮质中存在5HT1D受体，并直接证明了5HT1D受体的放射性配体结合测定可以监测该受体与GTP结合蛋白的相互作用。
