Upregulation of endothelium-derived hyperpolarizing factor compensates for the loss of nitric oxide in mesenteric arteries of dahl salt-sensitive hypertensive rats
| Autor: | Hideyuki Oniki, Toshio Ohtsubo, Kenichi Goto, Takanari Kitazono, Kiyoshi Matsumura, Yasuo Kansui |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
Male
Endothelium-derived hyperpolarizing factor medicine.medical_specialty Physiology Muscle Relaxation Vasodilator Agents Blood Pressure Nitric Oxide Muscle Smooth Vascular Nitric oxide Biological Factors Potassium Channels Calcium-Activated chemistry.chemical_compound Heart Rate Isometric Contraction Internal medicine Internal Medicine medicine Animals Nitric Oxide Donors Mesenteric arteries Rats Inbred Dahl Body Weight Sodium Dietary Iberiotoxin Hyperpolarization (biology) Acetylcholine Potassium channel Electrophysiological Phenomena Mesenteric Arteries Rats Endocrinology medicine.anatomical_structure chemistry Hypertension cardiovascular system Sodium nitroprusside Peptides Cardiology and Cardiovascular Medicine medicine.drug |
| Zdroj: | Hypertension Research. 35:849-854 |
| ISSN: | 1348-4214 0916-9636 |
| DOI: | 10.1038/hr.2012.36 |
| Popis: | This study was designed to determine whether a high-salt diet would alter endothelial function and, if so, the relative contributions of endothelium-derived hyperpolarizing factor (EDHF) and nitric oxide (NO) to any changes in vasomotor responses. Male Dahl salt-sensitive (DS) rats were given either a high-salt diet (8% NaCl, DS-H) or a low-salt diet (0.4% NaCl, DS-L) for 6 weeks. Membrane potentials and contractile responses were recorded from the isolated superior mesenteric arteries. After salt loading, DS-H developed hypertension, while DS-L remained normotensive. No difference was found in acetylcholine (ACh)-induced, endothelium-dependent relaxation between the groups. However, after treatment with indomethacin and NO synthase inhibitor, EDHF-like relaxation was significantly greater in DS-H than in DS-L. In contrast, NO-mediated relaxation was significantly smaller in DS-Hthan in DS-L. Iberiotoxin (IbTx), a specific blocker of large-conductance calcium-dependent potassium (BKCa) channels, attenuated EDHF-like relaxation in DS-H but not in DS-L. IbTx marginally inhibited EDHF-mediated hyperpolarization only in DS-H. Endothelium-independent relaxation in response to sodium nitroprusside or levcromakalim was similar in both groups. In conclusion, EDHF-like relaxation is upregulated through the activation of BKCa channels in the mesenteric arteries of DS-H. As the overall relaxation in response to ACh did not differ between the groups, the upregulation of EDHF appears to compensate for the loss of NO in the mesenteric arteries of DS-H. |
| Databáze: | OpenAIRE |
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