title: 5-Hydroxytryptamine-induced contractions of the human isolated saphenous vein: involvement of 5-HT2 and 5-HT1D-like receptors, and a comparison with grafted veins.
abstract: The receptors mediating the contractile effect of 5-hydroxytryptamine (5-HT) on the human isolated saphenous vein, obtained from 42 patients undergoing coronary bypass surgery, have been further characterized using a number of 5-HT-related drugs. The rank order of agonist potency was 5-carboxamidotryptamine (5-CT) approximately 5-HT greater than methysergide approximately sumatriptan approximately alpha-methyl-5-HT approximately 5-methoxy-3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indolesuccinate (RU 24969) approximately 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane hydrochloride (DOI) greater than 2-methyl-5-HT greater than 8-hydroxy-2(di-n-propylamino)tetralin (8-OH-DPAT). Flesinoxan was inactive as an agonist. Ketanserin (1 mumol/l) hardly affected sumatriptan-induced contractions but it caused a rightward shift of the upper part of the concentration-response curve of 5-HT and 5-CT. The same concentration of ketanserin caused a parallel rightward shift of the concentration-response curves of alpha-methyl-5-HT and DOI with pKB values of 7.1 and 7.1, respectively. The responses to sumatriptan were antagonized by methiothepin (0.1 mumol/l), metergoline (0.1 and 1 mumol/l), rauwolscine (1 mumol/l) and cyanopindolol (1 mumol/l); the calculated pKB values were 7.3, 6.9, 7.3, 6.7 and 6.5, respectively. Contractions to 5-HT were antagonized by methysergide (1 mumol/l), methiothepin (0.1 mumol/l; pKB = 7.1), ICS 205-930 (1 mumol/l; pKB = 5.9) and flesinoxan (30 mumol/l; pKB = 5.3). Remarkably, the contractions elicited by 2-methyl-5-HT were not attenuated by ICS 205-930, but were antagonized by methiothepin (0.1 mumol/l) and, more markedly, by ketanserin (1 mumol/l).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Pharmacology, Faculty of Medicine and Health Sciences, Erasmus University, Rotterdam, The Netherlands.
authors.forename: W A
authors.initials: WA
authors.lastname: Bax
authors.forename: D
authors.initials: D
authors.lastname: Van Heuven-Nolsen
authors.forename: E
authors.initials: E
authors.lastname: Bos
authors.forename: M L
authors.initials: ML
authors.lastname: Simoons
authors.forename: P R
authors.initials: PR
authors.lastname: Saxena
mesh_terms: D001026:Coronary Artery Bypass; D006633:Histamine Antagonists / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D011985:Receptors, Serotonin / Q000187:drug effects / Q000502:physiology; D012501:Saphenous Vein / Q000187:drug effects* / Q000637:transplantation; D012701:Serotonin / Q000494:pharmacology*; D014661:Vasoconstriction / Q000187:drug effects*
chemical_list: D006633:Histamine Antagonists; D011985:Receptors, Serotonin; D012701:Serotonin