Cardiovascular Effects Of Chronic Nitric Oxide Synthase Inhibition In Genetically Hypertensive Rats
| Autor: | Janet M. Ledingham, Stefan J Orange, Richard Laverty |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
Aging
medicine.medical_specialty Physiology Blood Pressure Cardiomegaly Vasodilation Left ventricular hypertrophy Nitric oxide chemistry.chemical_compound Heart Rate Physiology (medical) Internal medicine medicine Animals Enzyme Inhibitors Rats Wistar Pharmacology Dose-Response Relationship Drug biology Chemistry Hemodynamics medicine.disease Hindlimb Rats Nitric oxide synthase NG-Nitroarginine Methyl Ester Endocrinology Blood pressure Regional Blood Flow Hypertension biology.protein Hypertrophy Left Ventricular Sodium nitroprusside Nitric Oxide Synthase Perfusion Acetylcholine medicine.drug |
| Zdroj: | Clinical and Experimental Pharmacology and Physiology. 27:488-493 |
| ISSN: | 1440-1681 0305-1870 |
| DOI: | 10.1046/j.1440-1681.2000.03279.x |
| Popis: | SUMMARY 1. The possible role of an endothelial defect in the hypertension of the New Zealand genetically hypertensive (GH) rat strain was assessed by examining cardiovascular responses to the nitric oxide synthase (NOS) inhibitor Nω-nitro- L-arginine methyl ester ( L-NAME) and the endothelium-dependent depressor agent acetylcholine (ACh). The vascular sensitivity of the hindquarter to nitric oxide (NO) was examined using the NO donor sodium nitroprusside (SNP). 2. NG-Nitro- L-arginine methyl ester (10 mg/kg per day in drinking water) was given to GH and normotensive (N) rats from age 7–9 weeks, with GH and N untreated control groups. Systolic blood pressure (tail-cuff) was monitored weekly from age 5–9 weeks. At age 9 weeks, pressure responses to various vasoactive agents were measured in vivo and in the rat isolated hindquarter. Left ventricular (LV) mass was measured at the time of death. 3. NG-Nitro- L-arginine methyl ester induced a greater hypertensive effect in GH (P < 0.001) compared with N (P < 0.05) rats and caused a significant increase in hindquarter perfusion pressure in GH rats only (P < 0.01). 4. Genetically hypertensive rats had LV hypertrophy that was exacerbated by L-NAME (P < 0.01). Left ventricular hypertrophy was not induced by L-NAME in N rats. 5. The normalized response to ACh did not differ between GH and N control rats and was unaffected by L-NAME treatment in vivo and in vitro except at the highest ACh dose (3 μg/kg) in GH hindquarters (P < 0.01). The response to SNP was similar in GH and N hindquarters and enhanced by L-NAME in GH (0.1 μg; P < 0.05) and N rats (0.01 μg, P < 0.01; 0.1 μg, P < 0.001). 6. These results suggest that the L-arginine/NO system is not deficient in GH rats and that endothelial function in the GH hindquarter is preserved. They confirm that NO is involved in mediating blood pressure in GH and N rats and raise the possibility that a non-NO-mediated mechanism may underlie ACh-induced vasodilation in GH and N. |
| Databáze: | OpenAIRE |
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