Melatonin binding sites are functionally coupled to phosphoinositide hydrolysis in Syrian hamster RPMI 1846 melanoma cells

Eison, Arlene S.; Mullins, U. Lena

doi:10.1016/0024-3205(93)90494-n

Cited by 63 publications

(34 citation statements)

References 18 publications

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“…In the case of melatonin, some recent findings suggest the possibility of a calcium-dependent mechanism of inhibition. It has been recently shown that the low-affinity melatonin-binding sites in hamster melanoma cells are coupled to phosphoinositide hydrolysis (Eison and Mullins, 1993). It is, therefore, conceivable that melatonin binding to its low-affinity receptor might result in an increase in the intracellular levels of calcium.…”

Section: Discussionmentioning

confidence: 99%

Melatonin Antagonizes α‐Melanocyte‐Stimulating Hormone Enhancement of Melanogenesis in Mouse Melanoma Cells by Blocking the Hormone‐Induced Accumulation of the C Locus Tyrosinase

Valverde

Benedito

Solano

et al. 1995

European Journal of Biochemistry

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Melatonin was found to have a small inhibitory effect on tyrosinase activity and a slight stimulatory action on dopachrome tautomerase activity in B16 mouse melanoma cells. These effects were time and dose dependent, with the maximal response being observed after 24-48 h treatment and at concentrations of melatonin higher than the physiologic levels of the circulating hormone. Although these effects on the melanogenic activities were modest, incubation of melanocytes with melatonin prior to the addition of the melanotropin mediated a dramatic inhibition of a-melanocyte-stimulating-hormone-(a-MSH)-induced melanogenesis. This inhibitory effect was evident at melatonin concentrations as low as 10 nM. Inhibition was nearly total at 0.1 mM melatonin, even at high concentrations of a-MSH (1 pM).The inhibitory effect of melatonin on a-MSH stimulation of melanogenesis was investigated. Melatonin appeared to act at least at two stages. Pharmacological concentrations of melatonin diminished the number of a-MSH receptors to about 75% of the control values without an apparent effect on receptor affinity, as determined by receptor-binding studies using '251-[N-Leu4-~-Phe7]a-MSH as a probe. Physiological concentrations of melatonin also appeared to interfere with the intracellular events coupling increased CAMP levels and induction of the c locus tyrosinase, since it strongly inhibited the theophyllinemediated stimulation of melanogenesis. The inhibiton of tyrosinase stimulation was higher in the microsoma1 than in the melanosomal fractions of cells which were treated with melatonin, then exposed to either a-MSH (1 pM) or theophylline (1 mM), suggesting that one of the main effects of melatonin might be inhibition of the induction of tyrosinase de novo synthesis.Keywords : melatonin ; a-melanocyte-stimulating hormone ; tyrosinase ; tyrosinase-related proteins ; melanogenesis.Mammalian pigmentation is the result of melanin production by the epidermal melanocytes. Within melanocytes, melanin synthesis proceeds in specialized organelles, the melanosomes, through a series of coupled enzymic and chemical reactions (reviewed in Prota, 1992). The two initial steps of the pathway, rate-limiting hydroxylation of tyrosine to yield ~-3P-dihydroxyphenylalanine (L-Dopa) and L-Dopa oxidation to L-dopaquinone, are catalyzed by tyrosinase. These two reactions can also be catalyzed, although with lower efficiency, by the tyrosinaserelated protein-1 (TRP1; Jimenez et al., 1991 ; JimCnez-Cervantes et al., 1994) a protein encoded by the b Locus (Jackson, 1988). At least one other enzymic protein, dopachrome tautomerase (Aroca et al., 1990), has been shown to be involved in regulation of the pathway. This enzyme catalyzes the tautomerization of L-dopachrome, the product of spontaneous evolution

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Section: Discussionmentioning

confidence: 99%

Melatonin Antagonizes α‐Melanocyte‐Stimulating Hormone Enhancement of Melanogenesis in Mouse Melanoma Cells by Blocking the Hormone‐Induced Accumulation of the C Locus Tyrosinase

Valverde

Benedito

Solano

et al. 1995

European Journal of Biochemistry

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“…Activation of endogenous mt1 receptor expressed in the suprachiasmatic nucleus of the hypothalamus [Niles and Hashemi, 1990] or in ovine pars tuberalis cells [Morgan et al, 1994] as well as in transfected Chinese hamster ovary (CHO) [WittEnderby and Dubocovich, 1996] or COS-7 cells by melatonin results in a reduction of cAMP formation via pertussis toxin sensitive and insensitive G-proteins [Morgan et al, 1994;Witt-Enderby and Dubocovich, 1996;Brydon et al, 1999]. This receptor is capable of stimulating the Ca 2ϩ /IP 3 signaling pathway as well [Eison and Mullins, 1993;Ebisawa et al, 1994;Morgan et al, 1994;Popova and Dubocovich, 1994;McNulty et al, 1994;McArthur et al, 1997;Brydon et al, 1999;MacKenzie et al, submitted). Recent work has confirmed that the mt1 receptor signals through two inhibitory G␣ proteins (G i2 and G i3 ) that attenuate adenylyl cyclase activity and one stimulatory G␣ protein (G q/11 ) that increases phospholipase C activity [Brydon et al, 1999].…”

Section: Introductionmentioning

confidence: 98%

Melatonin induction of filamentous structures in non-neuronal cells that is dependent on expression of the human mt1 melatonin receptor

Witt‐Enderby

MacKenzie

McKeon

et al. 2000

Cell Motil. Cytoskeleton

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“…Melatonin and N-acetyl-serotonin (NAS) are thought to induce IP 3 generation in different systems such as hamster melanoma cells (17), pigeon brain (18), chick brain (19), and dinoflagellates (20). The ability of IP 3 to mobilize Ca 2+ from intracellular stores and therefore to trigger many biological processes such as cell division is well known (21).…”

Section: Introductionmentioning

confidence: 99%

Melatonin and N-acetyl-serotonin cross the red blood cell membrane and evoke calcium mobilization in malarial parasites

Hotta

Markus

Garcia

2003

Braz J Med Biol Res

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The duration of the intraerythrocytic cycle of Plasmodium is a key factor in the pathogenicity of this parasite. The simultaneous attack of the host red blood cells by the parasites depends on the synchronicity of their development. Unraveling the signals at the basis of this synchronicity represents a challenging biological question and may be very important to develop alternative strategies for therapeutic approaches. Recently, we reported that the synchrony of Plasmodium is modulated by melatonin, a host hormone that is synthesized only during the dark phases. Here we report that N-acetyl-serotonin, a melatonin precursor, also releases Ca 2+ from isolated P. chabaudi parasites at micro-and nanomolar concentrations and that the release is blocked by 250 mM luzindole, an antagonist of melatonin receptors, and 20 mM U73122, a phospholipase C inhibitor. On the basis of confocal microscopy, we also report the ability of 0.1 µM melatonin and 0.1 µM N-acetyl-serotonin to cross the red blood cell membrane and to mobilize intracellular calcium in parasites previously loaded with the fluorescent calcium indicator Fluo-3 AM. The present data represent a step forward into the understanding of the signal transduction process in the host-parasite relationship by supporting the idea that the host hormone melatonin and N-acetyl-serotonin generate IP 3 and therefore mobilize intracellular Ca 2+ in Plasmodium inside red blood cells.

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Melatonin binding sites are functionally coupled to phosphoinositide hydrolysis in Syrian hamster RPMI 1846 melanoma cells

Cited by 63 publications

References 18 publications

Melatonin Antagonizes α‐Melanocyte‐Stimulating Hormone Enhancement of Melanogenesis in Mouse Melanoma Cells by Blocking the Hormone‐Induced Accumulation of the C Locus Tyrosinase

Melatonin Antagonizes α‐Melanocyte‐Stimulating Hormone Enhancement of Melanogenesis in Mouse Melanoma Cells by Blocking the Hormone‐Induced Accumulation of the C Locus Tyrosinase

Melatonin induction of filamentous structures in non-neuronal cells that is dependent on expression of the human mt1 melatonin receptor

Melatonin and N-acetyl-serotonin cross the red blood cell membrane and evoke calcium mobilization in malarial parasites

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