Analysis of responses to 5-hydroxytryptamine (serotonin) in the hindlimb vascular bed of the cat

B. E. Winthrop, T. J. Bivalacqua, H. C. Champion, D. G. Lambert, C. T. Ilgenfritz, C. K. Jones, P. J. Kadowitz

Research output: Contribution to journalArticlepeer-review

Abstract

Responses to 5-HT, the 5-HT2 receptor agonist α-methyl-5-hydroxytryptamine maleate (α-Met 5-HT), and the 5-HT1 receptor agonist 5-carboxamidotryptamine maleate (5-CT) were investigated in the hindlimb vascular bed of the cat under constant flow conditions. 5-CT, a 5-HT1 selective agonist, has been shown to possess vasodilator activity in other vascular beds studied. Injections of 5-HT (0.3-30 μg), α-Met 5-HT (3-100 μg), and 5-CT (1-30 μg) into the hindlimb perfusion circuit caused dose-related increases in hindlimb perfusion pressure. Responses to 5-HT, α-Met 5-HT, and 5-CT were not altered by the cycloxgenase inhibitor, meclofenemate (2.5 mg/kg iv), or nonselective α-receptor blocking agent, phentolamine (1 mg/kg iv). Responses to 5-HT, α-Met 5-HT, and 5-CT were blocked by ketanserin (5 mg/kg iv), a 5-HT2 selective antagonist, in a dose that did not alter responses to norepinephrine, U46619 (thromboxane mimic), or angiotensin II. Moreover, responses to 5-HT, α-Met 5-HT and 5-CT were blocked by ketanserin and a vasodilator response was not unmasked. These data suggest that the responses to 5-HT, α-Met 5-HT and 5-CT are not dependent on the activation of α-receptors, thromboxane receptors, or angiotensin receptors but are modulated by 5-HT receptors in the hindlimb vascular bed of the cat. Furthermore, these data may be interpreted to suggest that 5-HT1 receptors do not play an active role in mediating responses to 5-HT in the hindlimb vascular bed of the cat.

Original languageEnglish (US)
Pages (from-to)A697
JournalFASEB Journal
Volume12
Issue number5
StatePublished - Mar 20 1998
Externally publishedYes

ASJC Scopus subject areas

  • Biotechnology
  • Biochemistry
  • Molecular Biology
  • Genetics

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