Document Detail

Melatonin interactions with blood pressure and vascular function during L-NAME-induced hypertension.
MedLine Citation:
PMID:  20041987     Owner:  NLM     Status:  MEDLINE    
The mechanisms responsible for the antihypertensive effect of melatonin are not completely understood. To elucidate the possible role of the nitric oxide (NO) pathway in the hemodynamic actions of melatonin, the effects of this indolamine on vascular function during hypertension induced by the NO-synthase (NOS) inhibitor, N(omega)-nitro-L-arginine-methyl ester (L-NAME) were investigated. Four groups of male adult Wistar rats were employed: control, L-NAME (40 mg/kg), melatonin (10 mg/kg) and L-NAME + melatonin for 5 wks. Systolic and diastolic blood pressure were measured invasively in the carotid artery. Conjugated dienes concentration (an oxidative load marker), NOS RNA expression and its activity and RNA expression of cyclooxygenase-(COX)-1 and COX-2 were determined in the aorta. Acetylcholine-induced responses and their NO-mediated component were evaluated in femoral and mesenteric artery. Moreover, endothelium-derived constricting factor (EDCF)-dependent vasoconstriction and inner diameter were determined in the femoral artery. Chronic L-NAME treatment induced hypertension, elevated the oxidative load and inhibited NOS activity. Moreover, impaired NO-dependent relaxation, augmented EDCF-constriction, increased COX-2 expression and reduced arterial inner diameter were observed. Melatonin added to L-NAME treatment completely prevented elevation of the oxidative load in the aorta. However, melatonin was not able to prevent NOS activity decline, elevation of COX-2 expression or the impairment of vascular responses (except moderate improvement in relaxation of small mesenteric arteries) and it exerted only slight antihypertensive effect. In conclusion, in addition to the reduction of the oxidative load, the restoration of the NO pathway seems to play an important role in the antihypertensive effect of melatonin.
Ludovit Paulis; Olga Pechanova; Josef Zicha; Andrej Barta; Roman Gardlik; Peter Celec; Jaroslav Kunes; Fedor Simko
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-12-23
Journal Detail:
Title:  Journal of pineal research     Volume:  48     ISSN:  1600-079X     ISO Abbreviation:  J. Pineal Res.     Publication Date:  2010 Mar 
Date Detail:
Created Date:  2010-05-03     Completed Date:  2010-07-26     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8504412     Medline TA:  J Pineal Res     Country:  Denmark    
Other Details:
Languages:  eng     Pagination:  102-8     Citation Subset:  IM    
Center for Cardiovascular Research, Charite-Universitatsmedizin, Berlin, Germany.
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MeSH Terms
Acetylcholine / pharmacology
Antihypertensive Agents / pharmacology
Blood Pressure / drug effects
Cyclooxygenase 2 / biosynthesis
Endothelins / pharmacology
Hypertension / chemically induced,  physiopathology*
Melatonin / pharmacology*
NG-Nitroarginine Methyl Ester
Nitric Oxide Synthase / metabolism
Rats, Wistar
Vasodilation / drug effects*
Reg. No./Substance:
0/Antihypertensive Agents; 0/Endothelins; 50903-99-6/NG-Nitroarginine Methyl Ester; 51-84-3/Acetylcholine; 73-31-4/Melatonin; EC Oxide Synthase; EC 2; EC protein, rat

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