Melatonin mediates two distinct responses in vascular smooth muscle

Doolen, Suzanne; Krause, Diana N.; Dubocovich, Margarita L.; Duckles, Sue Piper

doi:10.1016/s0014-2999(98)00064-8

Cited by 202 publications

(180 citation statements)

References 4 publications

Supporting

Mentioning

162

Contrasting

Unclassified

Order By: Relevance

“…15 Activation of the MT 1 receptor causes vasoconstriction in the rat caudal artery, which is believed to be involved in the thermoregulation, 16 and activation of MT 2 results in vasodilatation. 17 Currently, the exact mechanism determining the activation of melatonin receptor subtypes by melatonin is obscure. Another important question is whether the density or activity of melatonin receptors is altered during hypertension.…”

Section: Introductionmentioning

confidence: 99%

Effect of L-NAME-induced hypertension on melatonin receptors and melatonin levels in the pineal gland and the peripheral organs of rats

et al. 2009

View full text Add to dashboard Cite

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 (n¼36) treated with NO-synthase inhibitor L-NAME (40 mg kg À1 ) and age-matched controls (n¼36). 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. INTRODUCTIONMelatonin is a hormone produced by the pineal gland in a circadian manner and exhibits a broad spectrum of effects, including those in the cardiovascular system. Melatonin has been suggested to play a role in blood pressure (BP) control. Earlier reports have shown that pinealectomized rats developed hypertension, 1 and the administration of melatonin in this model normalized the increased BP. 2 Melatonin decreased BP in hypertensive patients, 3 and the addition of melatonin to antihypertensive medication in patients with nocturnal hypertension reduced nighttime systolic BP. 4 However, the mechanisms behind melatonin's effect on BP are still not completely understood.The hypotensive effect of melatonin could be mediated either by a direct effect on vessels or by decreasing brain serotonin release, resulting in sympathetic inhibition or parasympathetic stimulation. 5 There are rather limited data about changes of melatonin concentrations related to essential hypertension in the literature. Plasma melatonin and urinary 6-sulfatoxymelatonin levels have been reported

show abstract

Section: Introductionmentioning

confidence: 99%

Effect of L-NAME-induced hypertension on melatonin receptors and melatonin levels in the pineal gland and the peripheral organs of rats

et al. 2009

View full text Add to dashboard Cite

show abstract

“…Geary et al, (1998) suggested that melatonin inhibits endothelial K+ channels to decrease flow-induced release of nitric oxide as well as block smooth muscle K+ channels to enhance vascular tone. A few recent publications indicated a vasoconstrictive effect of melatonin in cerebral, caudal and coronary arteries via activation of either melatonin 1 or melatonin 2 membrane receptors in experimental animals and humans (Laitinen et al, 1992;Viswanathan et al, 1993;Doolen et al, 1998;Regrigny et al, 1999;Ekmekcioglu et al, 2001;Vandeputte et al, 2001;Masana et al, 2002;Pogan et al, 2002;Chucharoen et al, 2003;O'Rourke et al, 2003). Regrigny et al (2001) demonstrated that melatonin deprival makes the arteriolar wall thinner and decreases distensibility of the cerebral arteriolar wall.…”

Section: Discussionmentioning

confidence: 99%

“…Although the effects of the pineal hormone melatonin on vascular smooth muscle and vascular reactivity are described in last decade, morphological changes in the vessel are not yet clearly established (Shibata et al, 1989;Weekley, 1995;Muck et al, 1996;Mahle et al, 1997;Doolen et al, 1998;Monroe and Watts, 1998;Anwar et al, 2001;Vandeputte et al, 2001;Pache et al, 2002). Several studies have shown that pinealectomy reduces vascular wall thickness and melatonin treatment restores normal wall thickness and luminal diameter via melatonin receptors (Regrigny et al, 1999;Regrigny et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Effects Of Pınealectomy On Morphologıcal Features Of Blood Vessel In Chıcken: An Electron Mıcroscopıc And Stereologıcal Study

TURGUT¹,

Kaplan²,

ÜNAL³

et al. 2009

jecm

View full text Add to dashboard Cite

Although the effects of melatonin on vascular smooth muscle and vascular reactivity are described in last decade, the effects of melatonin on vascular tissues are still vague. The current study investigated the effects of pinealectomy on the blood vessel wall in the chicken. Fifteen chicks were divided into three groups, namely unoperated control, sham-operated and pinealectomized chicks. At the end of the experiment, a quantitative structural analysis of 15 sciatic artery samples from these groups was investigated. Effects of pinealectomy were quantified using volume fraction approach of stereological method. In this study, total cross-sectional area of the artery in pinealectomy group was significantly higher than those in unoperated control and sham-operated animals (p < 0.05). However, surgical pinealectomy procedure resulted in a significantly decreased thickness of the tunica adventitia of the vessel wall, in contrast to those of tunica media (p < 0.01). The present results indicate that pinealectomy had a vasodilator effect on the sciatic artery. In the light of current study, the structural changes in the vessel demonstrated by quantitative morphometric methods have been interpreted as a reflection of the role of melatonin on vessel wall and vascular reactivity, but this suggestion need to be validated in the human setting.

show abstract

“…Melatonin, which regulates various biological functions through 3 different subtypes of receptors, MTNR1A, MTNR1B, and MTNR1C, is involved in numerous physiological processes including blood pressure regulation (Doolen et al, 1998), circadian entrainment , retinal physiology (Bordt et al, 2001), oncogenesis (Bordt et al, 2001), seasonal reproduction (Barrett et al, 1997), ovarian physiology (Clemens et al, 2001), and osteoblast differentiation (Barrett et al, 1997;Roth et al, 1999;Clemens et al, 2001). The MTNR1A and MTNR1B receptor subtypes, encoded by genes on human chromosomes 4 and 11, respectively, are present in humans and other mammals, while an additional melatonin receptor subtype, MTNR1C, has been identified in fish, amphibians, and birds.…”

Section: Introductionmentioning

confidence: 99%

Expression patterns of melatonin receptors in chicken ovarian follicles affected by monochromatic light

Li¹,

Wu²,

Tu³

et al. 2015

Genet. Mol. Res.

View full text Add to dashboard Cite

ABSTRACT. Artificial illumination is an important exogenous factor in the control of many physiological and behavioral processes as well as an important environmental factor in the management of laying hens. Melatonin receptors are members of the G protein-coupled receptor family. The hormone melatonin is secreted primarily by the pineal gland, with highest levels occurring during the dark period of a circadian cycle. The aim of this study was to examine the effect of monochromatic light on chicken egg reproduction and expression of melatonin receptors in chicken ovarian follicles. A total of 552 19-week-old hens were randomly divided into 4 groups with 138 birds in each group. Each group was randomly divided into 3 replicates with 46 birds in each replicate. Feed and water were provided for ad libitum. Light treatments were: control cool white (400-760 nm), blue (480 nm), green (560 nm), and red (660 nm). The short wavelength (blue light) group produced a greater total number of eggs at 300 days of age than did the long wavelength (red light) group, and the red light group showed higher melatonin receptor type 1A and melatonin receptor 10073 Expression patterns of melatonin receptors in chicken ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 14 (3): 10072-10080 (2015) type 1C mRNA and protein expression. These results suggest that the wavelength of light is closely related to chicken egg number at 300 days of age; there is no effect of monochromatic light on melatonin receptor type 1B.

show abstract

Melatonin mediates two distinct responses in vascular smooth muscle

Cited by 202 publications

References 4 publications

Effect of L-NAME-induced hypertension on melatonin receptors and melatonin levels in the pineal gland and the peripheral organs of rats

Effect of L-NAME-induced hypertension on melatonin receptors and melatonin levels in the pineal gland and the peripheral organs of rats

Effects Of Pınealectomy On Morphologıcal Features Of Blood Vessel In Chıcken: An Electron Mıcroscopıc And Stereologıcal Study

Expression patterns of melatonin receptors in chicken ovarian follicles affected by monochromatic light

Contact Info

Product

Resources

About