Effect of L-NAME-induced hypertension on melatonin receptors and melatonin levels in the pineal gland and the peripheral organs of rats
| Autor: | Kristina Krajcirovicova, Michal Zeman, Iveta Herichová, Katarína Stebelová, Miroslava Benova, Ludovit Paulis, Fedor Simko |
|---|---|
| Rok vydání: | 2009 |
| Předmět: |
Male
endocrine system medicine.medical_specialty Light Physiology Blotting Western Radioimmunoassay Receptors Melatonin Biology Kidney Pineal Gland Melatonin receptor Melatonin Pineal gland Internal medicine Internal Medicine medicine Animals RNA Messenger Circadian rhythm Enzyme Inhibitors Rats Wistar Receptor Aorta Reverse Transcriptase Polymerase Chain Reaction Myocardium Circadian Rhythm Rats NG-Nitroarginine Methyl Ester Blood pressure Endocrinology medicine.anatomical_structure Hypertension Nitric Oxide Synthase Cardiology and Cardiovascular Medicine hormones hormone substitutes and hormone antagonists medicine.drug |
| Zdroj: | Hypertension Research. 32:242-247 |
| ISSN: | 1348-4214 0916-9636 |
| Popis: | Melatonin plays a role in blood pressure (BP) control. The aim of this study was to determine whether melatonin concentrations and melatonin receptor levels are altered in L-NAME-treated, NO-deficient hypertensive rats. Two groups of male adult Wistar rats were investigated: rats (n=36) treated with NO-synthase inhibitor L-NAME (40 mg kg(-1)) and age-matched controls (n=36). BP was measured weekly by tail-cuff plethysmography. After 4 weeks, L-NAME administration increased BP (178+/-1 vs. control 118+/-1 mm Hg). At the end of treatment, rats were killed in regular 4 h intervals over a 24-h period. Melatonin concentrations in the plasma, pineal gland, heart and kidney and melatonin receptor (MT(1)) density in the aorta were determined. A significant daily rhythm of melatonin concentrations was found in the blood, pineal gland, kidney and heart of both control and hypertensive rats. Peak nighttime pineal melatonin concentrations were higher in L-NAME-treated rats than in controls (3.38+/-0.48 vs. 1.75+/-0.33 ng per pineal gland). No differences between both groups were found in melatonin concentrations in blood, kidney and heart or in the MT(1) receptor density in the aorta. Our results suggest that L-NAME treatment enhances melatonin production in the pineal gland, potentially by decreasing an inhibitory effect of NO on melatonin production in the pineal gland. However, the enhanced pineal melatonin formation was insufficient to increase melatonin concentrations in circulation, heart and kidney of L-NAME-treated rats, indicating an increased use of melatonin in hypertensive animals. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|