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PubMed · 9404411

[Decrease of vascular response to iloprost in diabetic rats].

J F Bouchard·E C Dumont·D Lamontagne
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Abstract

The functional dilatory response in the streptozotocin-induced diabetic rat was investigated using thoracic aortas and coronary microcirculation. The aortas were cut in 4 mm intact or denuded rings and mounted into 20-ml organ baths. Coronary microcirculation was evaluated with isolated hearts perfused under constant flow conditions. Firstly, vasodilation to iloprost (Ilo) was examined. Dose-response curves to Ilo (10 pM-10 microM) on phenylephrine (PE, 30 nM for endothelium-denuded, and 0.3 microM for intact) preconstricted rings of diabetics and age-matched controls were comparable (n = 6). Decreased vasodilation in diabetic group was observed when dose-response curves to Ilo (1 nM-0.1 microM) were realized in isolated hearts (-22 +/- 3.3% vs -46 +/- 3.9%, n = 6, p < 0.05). Secondly, dose-response curves to forskolin (FSK), an adenylate-cyclase activator, performed in hearts (1 nM-3 microM), and on PE preconstricted rings (10 pM-10 microM) of diabetics and age-matched controls were comparable. Finally, the effect of an activator of ATP sensitive potassium channels (KATP), cromakalim (CMK), was evaluated in coronary circulation (0.3 nM-3 microM) and in aortas (10 pM-10 microM). Decreased vasodilation to CMK was observed in diabetic hearts (-10.5 +/- 4.3 vs -30.1 +/- 2.8%, n = 6, p < 0.05). In conclusion, under our experimental conditions, diabetes affects selectively the coronary vasodilation to iloprost. This modification of vascular reactivity may be due to a decrease of KATP channels sensitivity but not to a decreased activity of adenylate-cyclase.

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Adenosine TriphosphateAdenylyl CyclasesAnimalsAorta, ThoracicColforsinCoronary VesselsCromakalimDiabetes Mellitus, ExperimentalIloprostPotassium ChannelsRatsRats, Sprague-DawleyStreptozocinVascular ResistanceVasodilationVasodilator AgentsComparative StudyEnglish AbstractJournal ArticleResearch Support, Non-U.S. Gov't

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J F Bouchard, E C Dumont, D Lamontagne. 1997. [Decrease of vascular response to iloprost in diabetic rats].. https://pubmed.ncbi.nlm.nih.gov/9404411/

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