文章基本信息

标题：Alpha-blocking Potencies of Antihypertensive Agents (Prazosin, Terazosin, Bunazosin, SGB-1534 and Ketanserin) Having with Quinazoline or Quinazolinedione as Assessed by Radioligand Binding Assay Methods in Rat Brain
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作者：Hiroshi TSUCHIHASHI ; Takafumi NAGATOMO
期刊名称：Biological and Pharmaceutical Bulletin
印刷版ISSN：0918-6158
电子版ISSN：1347-5215
出版年度：1989
卷号：12
期号：3
页码：170-174
DOI：10.1248/bpb1978.12.170
出版社：The Pharmaceutical Society of Japan
摘要：The comparative effects of antihypertensive agents, quinazoline or quinazolinedione residues (prazosin, bunazosin, terazosin, SGB-1534, and ketanserin), on the binding of [³H] prazosin, [³H] p-aminoclonidine and [³H] dihydroalprenolol ([³H] DHA) to α₁, α₂-, and β-adrenoceptors in the rat orain were examined using radioligand binding assay methods. pA₂ values were also obtained in the isolated rat aorta (α₁-adrenoceptor) using phenylephrine as an agonist. A strong inhibition by these drugs of [³H] prazosin binding to α₁-adrenoceptors was observed, while the inhibition of [³H] DHA binding to β-adrenoceptors and [³H] p-aminoclonidine binding to α₂-adrenoceptor was found to be very weak. The rank order of antagonistic potencies of these drugs against the α₁-adrenergic receptors was determined by inhibition constants (K_i) with SGB-1534=prazosin=bunazosin > terazosin > ketanserin. The pA₂ value of these drugs, in contrast, had prazosin with higher pA₂ value than that of SGB-1534. From these two different types of experiments, it was clear that these drugs antagonized α₁-adrenoceptors even in the central nervous system, and the side chains bound to quinazoline and quinazolinedione residues may play an important role in the antagonistic potencies for α₁-adrenoceptors in the central nervous system as in the peripheral tissues.
关键词：central nervous system