Melatonin restores endothelium-dependent relaxation in aortic rings of pancreatectomized rats
| Autor: | Daniel P. Cardinali, Carlos F. Reyes-Toso, Daniel Obaya-Naredo, Pinto Je, Ricardo R. Rodríguez, Laura M. Linares, C. R. Ricci |
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| Rok vydání: | 2005 |
| Předmět: |
Male
Nitroprusside medicine.medical_specialty Endothelium Muscle Relaxation Diabetes Mellitus Experimental Nitric oxide Melatonin chemistry.chemical_compound Pancreatectomy Endocrinology Internal medicine medicine Animals Rats Wistar Aorta Relaxation (psychology) Chemistry Acetylcholine Rats Diabetes Mellitus Type 1 Glucose NG-Nitroarginine Methyl Ester medicine.anatomical_structure Circulatory system cardiovascular system Endothelium Vascular Sodium nitroprusside medicine.drug Blood vessel |
| Zdroj: | Journal of Pineal Research. 39:386-391 |
| ISSN: | 1600-079X 0742-3098 |
| DOI: | 10.1111/j.1600-079x.2005.00262.x |
| Popis: | In rats turned hyperglycemic by a subtotal pancreatectomy, a decreased relaxation response of aortic rings to acetylcholine (ACh) was found; this effect was amplified by preincubation in a high glucose medium (44 mmol/L). The relaxation response to ACh did not occur in endothelium-denuded rings or after the aortic rings were exposed to l-nitro-arginine methyl ester [L-NAME, a nitric oxide (NO) synthase inhibitor]. Incubation with the NO donor sodium nitroprusside (SNP) restored the impaired relaxation response seen in endothelium-denuded or L-NAME-treated aortic rings. Pancreatectomy decreased the vasorelaxation of aortic rings caused by SNP. Only in pancreatectomized rats, incubation in a high glucose medium impaired the relaxation effect of SNP. To assess whether melatonin preincubation reversed the impaired relaxation response to ACh (intact endothelium aortic rings) or to SNP (endothelium-denuded or L-NAME-treated rings) in hyperglycemic rats, cumulative dose-response curves were performed in the presence of 10(-5) mol/L melatonin. Melatonin preincubation did not modify ACh-induced relaxation of aortic rings in a normal glucose concentration but was highly effective in preventing the impairment of relaxation caused by a high glucose solution. Melatonin was also effective in restoring the impaired SNP-induced vasorelaxation seen in endothelium-denuded or L-NAME-treated aortic rings from hyperglycemic rats. The results further support the improvement by melatonin of the endothelial-mediated relaxation in blood vessels of diabetic rats. |
| Databáze: | OpenAIRE |
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