Impairment of endothelium-dependent relaxation of superior mesenteric artery in genetically diabetic WBN/Kob rats

The endothelium-dependent relaxation of superior mesenteric arteries of Wistar and genetically diabetic WBN/Kob rats was compared. Endothelium-dependent relaxation induced by acetylcholine (ACh) and A23187 was depressed in WBN/Kob rats. Relaxation induced by sodium nitroprusside, an endothelium-independent agent, in strips from WBN/Kob rats was similar to that in strips from Wistar rats. Indomethacin (5 × 10−6 M) enhanced the relaxation responses to ACh in strips from both WBN/Kob and Wistar rats; however, endothelium-dependent relaxation induced by ACh remained attenuated in WBN/Kob rats. These results show that endothelium-dependent relaxation is impaired not only in thoracic aorta but also in superior mesenteric arteries in genetically diabetic rats.Key words: acetylcholine, A23187, sodium nitroprusside, indomethacin, genetically diabetic rats, endothelium-derived relaxing factor.