Vascular Melatonin Receptors

Viswanathan, Mohan; Laitinen, Jarmo T.; Saavedra, Juan M.

doi:10.1159/000109495

Cited by 47 publications

(29 citation statements)

References 19 publications

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“…Despite the growing recognition of a direct action of melatonin on peripheral tissues [32,[41][42][43][44][45] including the blood vessel [46][47][48][49], spleen [50][51][52], bursa of Fabricius [53], thymus [54], immune cells [55,56], gut [57][58][59][60][61][62], heart [63,64], lung [63,65], kidney [66][67][68], salt gland [69], adrenal [70][71][72], liver [73] and reproductive tissues [18][19][20][21][22][23][24][25][26][27][28][29][30][31], many of the molecular and cellular mechanisms of melatonin signaling on these target tissues remain undefined. In the past few years, our labora...…”

Section: Introductionmentioning

confidence: 99%

Biological Basis and Possible Physiological Implications of Melatonin Receptor- Mediated Signaling in the Rat Epididymis

Shiu¹,

Li²,

Siu³

et al. 2000

Neurosignals

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The mammalian epididymis plays an important role in sperm maturation, an important process of male reproduction. Specific high-affinity 2-[¹²⁵I]iodomelatonin binding sites, satisfying the pharmacokinetic properties of specific receptors, have been found in the rat corpus epididymis, suggesting a direct melatonin action on epididymal physiology. Subsequent molecular and cell biology studies have identified these 2-[¹²⁵I]iodomelatonin binding sites to be mt₁ (MEL_1A) and MT₂ (MEL_1B) melatonin receptor subtypes. Changes in the binding characteristics of these receptors in the rat corpus epididymis in response to castration and steroid hormones like testosterone and hydrocortisone indicated that these membrane melatonin receptors are biologically functional receptors, whose activities are differentially regulated by testosterone and hydrocortisone. These melatonin receptors are coupled to pertussis toxin (PTX)-sensitive G_i protein and probably participate in androgenic and adrenergic regulation of rat corpus epididymal epithelial cell functions. Furthermore, rat corpus epididymal epithelial cell proliferation was stimulated by melatonin, whose action was dependent on the concentration and duration of exposure to the hormone. Interestingly, an MT₂ receptor ligand (4-phenyl-2-propionamidotetraline, 4-P-PDOT) induced a stimulatory effect on epididymal epithelial cell proliferation similar to that produced by melatonin. In contrast, a nuclear melatonin receptor agonist (1-[3-allyl-4-oxo-thiazolidine-2-ylidene]-4-methyl-thiosemi-carbazone, CGP52608) and 8-bromo-cAMP inhibited epididymal epithelial cell proliferation. Taken together, our data lead us to postulate that one of the possible physiological functions of melatonin on the rat epididymis is the stimulation of mt₁ and MT₂ melatonin receptors resulting in the inhibition of cAMP signaling and an increase in epithelial cell proliferation.

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Section: Introductionmentioning

confidence: 99%

Biological Basis and Possible Physiological Implications of Melatonin Receptor- Mediated Signaling in the Rat Epididymis

Shiu¹,

Li²,

Siu³

et al. 2000

Neurosignals

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“…Melatonin receptors have been localized in the hypothalamus and the pituitary of many species confirming a central site of action for melatonin in these processes (Vanecek et al 1987, Morgan et al 1989, Weaver et al 1993, Reppert et al 1994. However, based on the identification of putative melatonin binding sites in peripheral tissues such as the intestine (Pointoire et al 1993), cerebral arteries (Viswanathan et al 1993) and kidney (Song et al 1993(Song et al , 1995a(Song et al ,b, 1997 it is now thought that melatonin may have a potentially wider role than the control of seasonal and circadian rhythmicity. Furthermore, the identification of 2-[ 125 I]iodomelatonin binding sites in the fetuses of a number of different species, including the rat (Williams et al 1991), sheep (Helliwell & Williams 1994), hamster (Weaver et al 1988, Carlson et al 1991, Rivkees & Reppert 1992) and the human (Yuan et al 1991), is indicative of a further function for melatonin in fetal development.…”

Section: Introductionmentioning

confidence: 99%

Melatonin receptors in the human fetal kidney: 2-[125I]iodomelatonin binding sites correlated with expression of Mel1a and Mel1b receptor genes

Drew¹,

Williams²,

Hannah³

et al. 1998

Journal of Endocrinology

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Melatonin receptors in the human fetal kidney were identified and characterized by quantitative in vitro autoradiography using the melatonin agonist, 2-[ 125 I]iodomelatonin. Specific binding was localized to cells in the nephrogenic region at the outer perimeter of the developing kidney and was time-dependent, saturable and inhibited in the presence of guanosine 5 -0-(3-thiotriphosphate) indicative of a G protein-coupled receptor. Expression of the Mel1a and Mel1b melatonin receptors in human fetal kidney was determined using RT-PCR. In situ hybridization confirmed the localization of the Mel1a mRNA transcripts. A role for melatonin in development of the human fetal kidney is postulated.

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“…The same dose added to the high endogenous melatonin content at night may elicit an effect which, however, can be considered pharmacological. The hypotensive effect of melatonin and its vascular receptors were described in mammals (Zanoboni & Zanoboni-Muciaccia, 1967;Birau et al 1981; Kawashima et al 1987;Viswanathan, Laitinen & Saavedra, 1993;Cagnacci, Arangino, Angiolucci, Mascio, Longu & Melis, 1997). The cardiovascular response to melatonin may be exerted in part by the direct action of the hormone on blood vessels, in addition to a reduction in noradrenaline activity.…”

Section: Discussionmentioning

confidence: 99%

Effects of arginine vasotocin, isotocin and melatonin on blood pressure in the conscious atlantic cod (Gadus morhua): hormonal interactions?

Kulczykowska

1998

Experimental Physiology

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SUMMARYThe effects of exogenous arginine vasotocin (AVT), isotocin (IT) and melatonin on the blood pressure of conscious Atlantic cod (Gadus morhua) were examined. Ventral aortic blood pressure (PVA) was recorded from a cannula inserted into the afferent branchial artery of the third gill arch.Dorsal aortic blood pressure (PDA) was recorded via a cannula implanted into the efferent branchial artery in the same gill arch. Each fish received two doses (10 and 50 ng kg-') of AVT, IT and melatonin. AVT was also administered in combination with melatonin. Injection of 10 ng kg-1 AVT produced significant hypertension, especially in animals injected during the daytime. In contrast, the same dose of IT induced no significant change in either PVA or PDA.Administration of 10 ng kg-' melatonin at night caused a long-lasting decrease in both parameters.Melatonin also inhibited the increase in blood pressure elicited by AVT. These results indicate that AVT, but not IT, is vasopressor in the cod. The effects of combined administration of melatonin and AVT show the antihypertensive action of melatonin in AVT-induced hypertension.

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Vascular Melatonin Receptors

Cited by 47 publications

References 19 publications

Biological Basis and Possible Physiological Implications of Melatonin Receptor- Mediated Signaling in the Rat Epididymis

Biological Basis and Possible Physiological Implications of Melatonin Receptor- Mediated Signaling in the Rat Epididymis

Melatonin receptors in the human fetal kidney: 2-[125I]iodomelatonin binding sites correlated with expression of Mel1a and Mel1b receptor genes

Effects of arginine vasotocin, isotocin and melatonin on blood pressure in the conscious atlantic cod (Gadus morhua): hormonal interactions?

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