title: Vasoconstrictor effects of leukotrienes C4 and D4 in the feline mesenteric vascular bed.
abstract: The effects of leukotriene C4 (LTC4) and leukotriene D4 (LTD4) in the feline mesenteric vascular bed were investigated under conditions of controlled blood flow so that changes in perfusion pressure directly reflect changes in vascular resistance. Intra-arterial injections of LTC4 and LTD4 (0.3-3.0 micrograms) increased perfusion pressure in a dose-related fashion. Vasoconstrictor responses to LTC 4 and LTD4 were similar to norepinephrine (NE) whereas mesenteric vasoconstrictor response to the thromboxane analog, U46619, was markedly greater than were responses to LTC4 and LTD4. Meclofenamate in a dose that greatly attenuated the systemic depressor response to arachidonic acid was without effect on vasoconstrictor responses to LTC4 and LTD4, NE and U46619 in the mesenteric vascular bed. The present data show that LTC4 and LTD4 possess significant vasoconstrictor activity in the feline mesenteric vascular bed. In addition, the present data suggest that products of the cyclooxygenase pathway do not mediate vasoconstrictor responses to LTC4 and LTD4 in the intestinal circulation of the cat.
mesh_terms: D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D002415:Cats; D004305:Dose-Response Relationship, Drug; D005260:Female; D008297:Male; D008469:Meclofenamic Acid / Q000494:pharmacology; D008638:Mesenteric Arteries / Q000187:drug effects / Q000502:physiology*; D009638:Norepinephrine / Q000494:pharmacology; D011450:Prostaglandin Endoperoxides, Synthetic / Q000494:pharmacology; D012039:Regional Blood Flow / Q000187:drug effects; D013189:SRS-A / Q000494:pharmacology*; D014661:Vasoconstriction / Q000187:drug effects*
chemical_list: D001095:Arachidonic Acids; D011450:Prostaglandin Endoperoxides, Synthetic; D013189:SRS-A; D016718:Arachidonic Acid; D008469:Meclofenamic Acid; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D009638:Norepinephrine