Arachidonic acid-induced vasodilation of rat small mesenteric arteries is lipoxygenase-dependent

Allison W. Miller, Prasad V.G. Katakam, Hon chi Lee, Christina D. Tulbert, David W. Busija, Neal L. Weintraub

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43 Scopus citations


We examined the mechanism of arachidonic acid-induced vasodilation in rat small mesenteric arteries and determined the primary arachidonic acid metabolites produced by these arteries. Responses to arachidonic acid in small mesenteric arteries from Sprague-Dawley rats were investigated in vitro in the presence or absence of endothelium or after pretreatment with inhibitors of nitric oxide (NO), cyclooxygenase, cytochrome P450, lipoxygenase, or K+ channels. In addition, the metabolism of arachidonic acid was examined by incubating arteries with [3H]arachidonic acid in the presence and absence of cyclooxygenase, cytochrome P450, or lipoxygenase inhibitors. Finally, the vascular response to both 12(S)-hydroxyeicosatetraenoic acid (HETE) and 12(S)-hydroperoxyeicosatetraenoic acid (HPETE) was determined. Arachidonic acid induced an endothelium-dependent vasodilation that was abolished by lipoxygenase inhibitors [cin-namyl-3,4-dihydroxy-cyanocinnamate (CDC) or 5,8,11-eicosatriynoic acid (ETI)] and KCI, whereas it was partially inhibited by either tetraethylammonium or iberiotoxin. In contrast, neither NO nor cytochrome P450 enzyme inhibitors affected arachidonic acid-mediated dilation, whereas inhibition of cyclooxygenase enhanced dilation. Biochemical analysis revealed that small mesenteric arteries primarily produce 12-HETE, a lipoxygenase metabolite. Moreover, CDC and ETI inhibited the production of 12-HETE. Finally, both 12(S)-HETE and 12(S)-HPETE induced a concentration-dependent vasodilation in mesenteric arteries. These findings provide functional and biochemical evidence that the lipoxygenase pathway mediates arachidonic acid-induced vasodilation in rat small mesenteric arteries through a K+ channel-dependent mechanism.

Original languageEnglish (US)
Pages (from-to)139-144
Number of pages6
JournalJournal of Pharmacology and Experimental Therapeutics
Issue number1
StatePublished - Jan 1 2003
Externally publishedYes

ASJC Scopus subject areas

  • Molecular Medicine
  • Pharmacology


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