Increased prostanoid dependency of arterial relaxation in Chlamydia pneumoniae-infected mice.
Endothelial dysfunction plays an important role in the development of atherosclerosis. Previous studies have shown that inoculation with Chlamydia pneumoniae contributes to atherosclerotic development in rabbits and hypercholesterolaemic mice and causes endothelial dysfunction in apolipoprotein E-deficient mice. The effect of acute C. pneumoniae infection on endothelial function in normocholesterolaemic C57BL/6J mice was studied by measuring the force of contraction of the descending aorta after noradrenaline stimulation and in response to methacholine-induced relaxation. In addition, the effects of the nitric oxide synthase inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME) and the cyclooxygenase inhibitor diclofenac on relaxation were assessed. Pre-treatment of the aortas with L-NAME decreased the relaxation response in both the infected and uninfected groups and no significant difference was detected between these groups, whereas diclofenac significantly attenuated the relaxation response only in the infected animals. In conclusion, infection shifted the balance of endothelium-derived relaxing factors from nitric oxide towards vasorelaxing prostanoids in C57BL/6J mice.
Törmäkangas
Liisa
L
National Public Health Institute (KTL), PO Box 310, FIN-90101 Oulu, Finland.
Ketonen
Juha
J
Institute of Biomedicine, University of Helsinki, Finland.
Leinonen
Maija
M
National Public Health Institute (KTL), PO Box 310, FIN-90101 Oulu, Finland.
Saikku
Pekka
P
Department of Medical Microbiology, University of Oulu, Finland.
Paakkari
Ilari
I
Institute of Biomedicine, University of Helsinki, Finland.
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000503:physiopathology*; D023521:Chlamydophila Infections / Q000503:physiopathology*; D016993:Chlamydophila pneumoniae; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D004008:Diclofenac / Q000494:pharmacology; D004195:Disease Models, Animal; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D016210:Methacholine Chloride / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism; D009638:Norepinephrine / Q000494:pharmacology; D011453:Prostaglandins / Q000378:metabolism* / Q000494:pharmacology; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects
D016861:Cyclooxygenase Inhibitors; D004791:Enzyme Inhibitors; D011453:Prostaglandins; D014662:Vasoconstrictor Agents; D016210:Methacholine Chloride; D004008:Diclofenac; D009569:Nitric Oxide; D019331:NG-Nitroarginine Methyl Ester; D009638:Norepinephrine