Characterization of 5-HT receptors in simian isolated gastroepiploic artery.
The vascular responses of simian gastroepiploic arteries to 5-hydroxytryptamine (5-HT), 5-carboxamidotryptamine (5-CT, a selective 5-HT1-like receptor agonist), 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT, a selective 5-HT1A receptor agonist), m-trifluoromethylphenylpiperazine (TFMPP, a selective 5-HT1B receptor agonist), noradrenaline and KCl were examined in isolated, cannulated and perfused preparations. 5-HT induced dose-dependent vasoconstrictions more potently than noradrenaline did. The rank order of potency was 5-HT > noradrenaline > 5-CT >> 8-OH-DPAT = TFMPP. 5-HT- and 5-CT-induced vasoconstrictions were not significantly changed by endothelial denudation, although acetylcholine-induced vasodilatations were abolished. 5-HT-induced vasoconstrictions were depressed by phentolamine (an alpha-adrenoceptor antagonist), diltiazem (a calcium ion channel inhibitor), methysergide (a 5HT1- and 5HT2-receptor antagonist) and ketanserin (a selective 5-HT2 receptor antagonist). Noradrenaline-induced vasoconstrictions were readily inhibited by phentolamine and ketanserin. 5-CT-, 8-OH-DPAT- and TFMPP-induced vasoconstrictions were inhibited by both methysergide and ketanserin. KCl-induced vasoconstrictions were blocked by diltiazem. From these results, we conclude that (1) the simian gastroepiploic artery contains 5-HT receptors, (2) 5-HT1-like and 5-HT2 receptors are involved in the vasoconstriction of the simian gastroepiploic artery, and (3) the vasoconstriction is at least partially related to the activation of calcium ion channels.
Noguchi
M
M
Department of Pharmacology, Shinshu University School of Medicine, Matsumoto, Japan.
Nakane
T
T
Chiba
S
S
D000818:Animals; D001158:Arteries / Q000187:drug effects*; D004110:Diltiazem / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000502:physiology; D005260:Female; D066298:In Vitro Techniques; D007650:Ketanserin / Q000494:pharmacology; D008251:Macaca; D008297:Male; D008784:Methysergide / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D009852:Omentum / Q000098:blood supply; D010477:Perfusion; D010646:Phentolamine / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D011985:Receptors, Serotonin / Q000187:drug effects*; D012701:Serotonin / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D013270:Stomach / Q000098:blood supply; D014661:Vasoconstriction / Q000187:drug effects
D011985:Receptors, Serotonin; D017366:Serotonin Receptor Agonists; D012701:Serotonin; D011189:Potassium Chloride; D007650:Ketanserin; D004110:Diltiazem; D009638:Norepinephrine; D008784:Methysergide; D010646:Phentolamine