Reduced nitric oxide-mediated relaxation and endothelial nitric oxide synthase expression in the tail arteries of streptozotocin-induced diabetic rats

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• 作者：Siti Safiah Mokhtar^a ; Paul M. Vanhoutte^b ; Susan Wai Sum Leung^b ; Rapeah Suppian^c ; Mohd Imran Yusof^d ; Aida Hanum Ghulam Rasool^a ; ^{aidakb@usm.my" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Acetylcholine hydrochloride (PubChem CID ; 6060) ; Phenylephrine hydrochloride (PubChem CID ; 5284443) ; Streptozotocin (PubChem CID ; 29327) ; Sodium nitroprusside (PubChem CID ; 11963622) ; Ketamine hydrochloride (PubChem CID ; 15851) ; TRAM 34 (PubChem CID ; 656734) ; UCL 1684 (PubChem CID ; 656733) ; Salbutamol hemisulfate (PubChem CID ; 39859) ; Indomethacin (PubChem CID ; 3715) ; L-NAME hydrochloride (PubChem CID ; 135193) ; Prostacyclin (PubChem CID ; 5282411)
• 刊名：European Journal of Pharmacology
• 出版年：2016
• 出版时间：15 February 2016
• 年：2016
• 卷：773
• 期：Complete
• 页码：78-84
• 全文大小：1381 K

文摘

Diabetes is associated with endothelial dysfunction, which is characterized by impaired endothelium-dependent relaxations. The present study aimed to examine the role of nitric oxide (NO), prostacyclin and endothelium-dependent hyperpolarization (EDH), in the relaxation of ventral tail arteries of rats under diabetic conditions. Relaxations of tail arteries of control and diabetic rats were studied in wire myograph. Western blotting and immunostaining were used to determine the presence of proteins. Acetylcholine-induced relaxations were significantly smaller in arteries of diabetic compared to control rats (R_max; 70.81±2.48% versus 85.05±3.15%). Incubation with the combination of non-selective cyclooxygenase (COX) inhibitor, indomethacin and potassium channel blockers, TRAM 34 and UCL 1684, demonstrated that NO-mediated relaxation was attenuated significantly in diabetic compared to control rats (R_max; 48.47±5.84% versus 68.39±6.34%). EDH-type (in the presence of indomethacin and NO synthase inhibitor, LNAME) and prostacyclin-mediated (in the presence of LNAME plus TRAM 34 and UCL 1684) relaxations were not significantly reduced in arteries of diabetic compared to control rats [R_max: (EDH; 17.81±6.74% versus 34.16±4.59%) (prostacyclin; 15.85±3.27% versus 17.23±3.75%)]. Endothelium-independent relaxations to sodium nitroprusside, salbutamol and prostacyclin were comparable in the two types of preparations. Western blotting and immunostaining indicated that diabetes diminished the expression of endothelial NO synthase (eNOS), while increasing those of COX-1 and COX-2. Thus, since acetylcholine-induced NO-mediated relaxation was impaired in diabetes because of reduced eNOS protein expression, pharmacological intervention improving NO bioavailability could be useful in the management of diabetic endothelial dysfunction.