These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Studies on YM-12617: a selective and potent antagonist of postsynaptic alpha 1-adrenoceptors.
    Author: Honda K, Takenaka T, Miyata-Osawa A, Terai M, Shiono K.
    Journal: Naunyn Schmiedebergs Arch Pharmacol; 1985 Jan; 328(3):264-72. PubMed ID: 2858821.
    Abstract:
    YM-12617, 5-[2-[[2-(2-ethoxyphenoxy)ethyl]-amino]propyl]-2 -methoxybenzenesulfonamide HCl is a structurally new type of extremely potent alpha 1-adrenoceptor antagonist. Its alpha-adrenoceptor blocking properties have been compared with those of prazosin, phentolamine and yohimbine using both pharmacological and 3H-ligand binding techniques in vitro and in vivo. In the isolated rabbit aorta, a tissue known to contain mainly alpha 1-adrenoceptors at postjunctional sites, YM-12617 competitively antagonized noradrenaline-induced contraction with a pA2 value of 10.11. Although YM-12617 was also a competitive antagonist toward clonidine at prejunctional alpha 2-adrenoceptors in the isolated rat vas deferens, its affinity for these receptors (pA2 = 6.41) was 5,000 times lower than that displayed for the postjunctional alpha 1-adrenoceptors in the isolated rabbit aorta. YM-12617 displaced both 3H-WB 4101 and 3H-clonidine binding to rat brain membranes; however, the affinity of YM-12617 for alpha 1-adrenoceptors (pKi = 9.64) was 3800 times higher than that for alpha 2-adrenoceptors (pKi = 6.06). Based on pA2 values obtained in the isolated tissues and pKi values in the binding assays, YM-12617 was 2-18, 36-117 and 1,740-5,750 times more potent than prazosin, phentolamine and yohimbine in antagonizing alpha 1-adrenoceptors, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
    [Abstract] [Full Text] [Related] [New Search]