Functional 5-HT receptor subtypes in the isolated canine common carotid artery.
The vascular responses to 5-hydroxytrypamine (5-HT), 5-carboxamidotryptamine (5-CT, a selective 5-HT1-like receptor agonist), alpha-methyl-5-HT (alpha-M-5-HT, a relatively selective 5-HT2 receptor agonist), noradrenaline (NA), and KCl were examined in isolated, cannulated, and perfused canine common carotid arterial preparations. They caused strong vasoconstrictions. The rank order of vasoconstrictive potency was 5-HT > alpha-M-5-HT > or = NA > 5-CT >> KCl. The 5-HT-induced vasoconstriction was significantly depressed by methysergide (a 5-HT1 and 5-HT2 receptor antagonist), ketanserin (a selective 5-HT2 receptor antagonist), and spiperone (a selective 5-HT2 receptor antagonist). The 5-CT- and alpha-M-5-HT-induced vasoconstrictions were also significantly inhibited by methysergide, spiperone, and ketanserin. The NA-induced vasoconstriction was readily inhibited by bunazosin (an alpha-adrenoceptor antagonist) and ketanserin but not significantly inhibited by spiperone and methysergide. KCl has a weak potency for producing a vasoconstriction of the canine common carotid artery. A relatively large dose of diltiazem (a calcium channel-blocker) did not modify 5-HT-induced vasoconstrictions.(ABSTRACT TRUNCATED AT 250 WORDS)
Vhora
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Department of Neurosurgery, Shinshu University School of Medicine, Matsumoto, Japan.
Chiba
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D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D017536:Carotid Artery, Common / Q000737:chemistry* / Q000187:drug effects; D004110:Diltiazem / Q000494:pharmacology; D004285:Dogs; D005260:Female; D007650:Ketanserin / Q000494:pharmacology; D008297:Male; D008784:Methysergide / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D011799:Quinazolines / Q000494:pharmacology; D011985:Receptors, Serotonin / Q000145:classification / Q000187:drug effects / Q000502:physiology*; D012701:Serotonin / Q000031:analogs & derivatives / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D013134:Spiperone / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects
D000317:Adrenergic alpha-Antagonists; D011799:Quinazolines; D011985:Receptors, Serotonin; D017366:Serotonin Receptor Agonists; C042390:alpha-methylserotonin; D012701:Serotonin; D013134:Spiperone; D011189:Potassium Chloride; C047087:5-carboxamidotryptamine; D007650:Ketanserin; C018176:bunazosin; D004110:Diltiazem; D009638:Norepinephrine; D008784:Methysergide