Comparison of binding affinities of ω-conotoxin and amlodipine to N-type Ca~(2+) channels

• 作 者: 曲瑛莉 杉山健太郎 大贯敏雄 服部薰 渡边贤一 长友孝文
• 机 构: 新泻药科大学药理学教研室,新泻药科大学临床药理学教研室
• 出 处: Acta Pharmacologica Sinica
• 发表日期: 1998年02期
• 关键词: 钙通道 Ca Comparison N-type affinities amlodipine and binding brain channels

目的：用大鼠脑对ωｃｏｎｏｔｏｘｉｎ（ωＣＴＸ）及氨氯地平与Ｎ型钙通道的内在关系进行分析．方法：将大鼠全脑匀浆于ＨＥＰＥＳ５０ｍｍｏｌ·Ｌ－１（ｐＨ７４）缓冲液中，经４００００×ｇ离心后，收集膜区域．以１２５Ｉωｃｏｎｏｔｏｘｉｎ（ＣＴＸ）作为放射配体测定．结果：１２５ＩωＣＴＸ与冷冻标本及新鲜标本结合的Ｂｍａｘ无区别．Ｎ型钙通道的Ｋｄ和Ｂｍａｘ值分为００２±００１ｍｍｏｌ·Ｌ－１和１０２９±１０８ｐｍｏｌ／ｇ蛋白质．ωＣＴＸ及氨氯地平的ｐＫｉ值分别为９５７以及＜４，普萘洛尔、哌唑嗪、阿托品、组胺的ｐＫｉ值也非常低．结论：Ｌ型钙离子拮抗剂氨氯地平与Ｎ离子通道的亲和性很低．

OBJECTIVE: To analyze the intrinsic relationship between ωconotoxin (ωCTX) and amlodipine and N-type calcium channel in rat brain. Methods: Whole brain homogenate was collected in HEPES 50mmol·L-1 (pH74) buffer and centrifuged at 40,000 × g to collect the membrane area. To 125I    con-otoxin (CTX) as a radioligand assay. Results: 125I   CTX and frozen specimens and fresh specimens Bmax no difference. The Kd and Bmax values ​​of N-type calcium channel were divided into 002 ± 001 mmol·L-1 and 1029 ± 108 pmol / g protein. ω-CTX and amlodipine pKi values ​​were 9  57 and <4, pKi value of propranolol, prazosin, atropine, histamine is also very low. Conclusion: L-type calcium channel blocker amlodipine has low affinity with N channel.