title: Platelet-activating factor (PAF) has no direct effect on rat intracerebral arterioles in vitro.
abstract: We examined the effect of platelet activating-factor (PAF) on lumen diameter of penetrating intracerebral arterioles (diameter less than 50 microns) dissected from rat brains. PAF over a concentration range of 10(-12)-10(-6) M had no effect on lumen diameter. However, the arterioles were capable of both vasodilation in response to calcitonin gene-related peptide (EC50 = 4.4 nM) and vasoconstriction in response to the thromboxane mimetic, U44619 (EC50 = 5.8 nM). We conclude that the effects of PAF on the cortical circulation observed in vivo are indirect and may be due to PAF-induced changes in other humoral or cellular mediators.
authors.affiliation: Department of Pharmacology, SmithKline Beecham Pharmaceuticals, King of Prussia, PA 19406-0939.
authors.forename: R M
authors.initials: RM
authors.lastname: Edwards
authors.forename: W
authors.initials: W
authors.lastname: Trizna
authors.forename: G
authors.initials: G
authors.lastname: Feuerstein
mesh_terms: D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D000818:Animals; D001160:Arterioles / Q000187:drug effects*; D001921:Brain / Q000098:blood supply* / Q000187:drug effects; D015740:Calcitonin Gene-Related Peptide / Q000494:pharmacology; D010972:Platelet Activating Factor / Q000494:pharmacology*; D011450:Prostaglandin Endoperoxides, Synthetic / Q000494:pharmacology; D051381:Rats; D014661:Vasoconstriction / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects
chemical_list: D010972:Platelet Activating Factor; D011450:Prostaglandin Endoperoxides, Synthetic; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D015740:Calcitonin Gene-Related Peptide