Contractile effects of 8-hydroxy-2-(di-n-propylamino)tetralin and flesinoxan in human isolated basilar artery.
The aim of the present study was to assess the effects of the 5-HT1A receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) and flesinoxan in ring preparations of human basilar artery. 5-Hydroxytryptamine-(5-HT), 8-OH-DPAT and flesinoxan induced concentration-dependent contractions of human basilar artery, the rank order of agonist potency being 5-HT greater than 8-OH-DPAT approximately flesinoxan. The rank order of maximum response, relative to 5-HT was 5-HT (100%) much greater than 8-OH-DPAT (40.4 +/- 4.4%) much greater than flesinoxan (7.0 +/- 2.3%). The contractile effects of 8-OH-DPAT were blocked by phentolamine (10 microM) but not by labetalol (10 microM). Spiperone (1 microM) had no significant effect on either 5-HT or 8-OH-DPAT-induced contraction, however methiothepin (100 nM) produced inhibition of both 5-HT- and 8-OH-DPAT-induced contraction of human basilar artery. In addition, flesinoxan (100 microM) produced blockade of 5-HT-, 8-OH-DPAT- and sumatriptan (a 5-HT1-like receptor agonist)-induced contraction of human basilar artery, although full concentration-effect curves were not obtained. In some preparations 8-OH-DPAT produced a concentration-dependent relaxation of tone. This effect was particularly apparent in the presence of phentolamine. We conclude from the relative rank order of antagonist potency that 8-OH-DPAT and 5-HT produce contraction of the human basilar artery by activation of the same receptor, a 5-HT1-like receptor distinct from the 5-HT1A receptor subtype.(ABSTRACT TRUNCATED AT 250 WORDS)
Parsons
A A
AA
Department of Physiological Sciences, University of Manchester, U.K.
Motevalian
M
M
Whalley
E T
ET
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001488:Basilar Artery / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques; D007211:Indoles / Q000494:pharmacology; D008719:Methiothepin / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D010646:Phentolamine / Q000494:pharmacology; D010879:Piperazines / Q000494:pharmacology*; D011985:Receptors, Serotonin / Q000187:drug effects; D012701:Serotonin / Q000494:pharmacology; D012702:Serotonin Antagonists / Q000494:pharmacology; D013134:Spiperone / Q000494:pharmacology; D013449:Sulfonamides / Q000494:pharmacology; D018170:Sumatriptan; D013764:Tetrahydronaphthalenes / Q000494:pharmacology*; D014662:Vasoconstrictor Agents / Q000494:pharmacology
D000959:Antihypertensive Agents; D007211:Indoles; D010879:Piperazines; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D013449:Sulfonamides; D013764:Tetrahydronaphthalenes; D014662:Vasoconstrictor Agents; D012701:Serotonin; C056895:flesinoxan; D013134:Spiperone; D008719:Methiothepin; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D018170:Sumatriptan; D010646:Phentolamine