Rhythms in immunoreactive melatonin in the retina and harderian gland of rats: Persistence after pinealectomy

Reíter, Russel J.; Richardson, Bruce A.; Matthews, Susan A.; Lane, Shelly J.; Ferguson, Bonnie N.

doi:10.1016/0024-3205(83)90192-3

Cited by 160 publications

(64 citation statements)

References 24 publications

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“…These results suggest that retinal melatonin production is elevated at night, but release of melatonin from the eyecup is prevented by local metabolism. A similar mechanism may provide an explanation for the relatively small contribution of retinal melatonin to circulating levels in avian species (14,15) and the low melatonin content in the retina of mammals (24,25).…”

Section: Resultsmentioning

confidence: 99%

Retinal melatonin is metabolized within the eye of xenopus laevis.

Cahill

Besharse

1989

Proc. Natl. Acad. Sci. U.S.A.

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Section: Resultsmentioning

confidence: 99%

Retinal melatonin is metabolized within the eye of xenopus laevis.

Cahill

Besharse

1989

Proc. Natl. Acad. Sci. U.S.A.

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“…In a number of teleost species, rhythmic melatonin production by both tissues is in phase (low during day and high at night) while in some other vertebrates (including teleosts), melatonin production in retina can be reversed thus being higher during the day than at night (Gern et al, 1978;Yu et al, 1981;Reiter et al, 1983;Serino et al, 1993;Iigo et al, 1997;Besseau et al, 2006;Iigo et al, 2007b). These phase shift patterns of secretion could be linked to differences within the melatonin biosynthesis pathway leading to the production of melatonin and more specifically arylalkylamine N-acetyltransferase (AANAT) which is the enzyme found in all vertebrates involved in the conversion of serotonin into melatonin (Klein et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

Retinal light input is required to sustain plasma melatonin rhythms in Nile tilapia Oreochromis niloticus niloticus

Martinez-Chavez

Migaud

2009

Brain Research

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The aim of this work was to confirm previous findings suggesting that the eyes are required for night-time melatonin production in Nile tilapia and further characterise this divergent circadian organisation. To do so, melatonin levels were firstly measured in eyecups and plasma to determine circadian patterns of melatonin production.Secondly, the effect of partial ophthalmectomy on the suppression of melatonin production was determined in vivo as well as ex vivo pineal light/dark sensitivity.Finally, to investigate whether such findings could be related to post-surgery stress, melatonin analyses were performed in the subsequent 24 h and 7 days postophthalmectomy with cortisol levels assessed as an indicator of stress. Our results showed an inverse pattern of melatonin production in the eye cups of tilapia compared to blood circulating levels, suggesting different roles played by melatonin in these two tissues. Results then demonstrated that total or partial ophthalmectomy resulted in the suppression of night-time melatonin production. Furthermore, although pineals in culture were shown to be photosensitive, night-time melatonin levels were much lower than seen in other species. Finally, when performing sampling immediately or one week post-surgery, no difference in the melatonin profiles were observed. It is therefore unlikely that post-surgery stress would explain such suppression in melatonin production although all fish displayed high cortisol levels most probably due to social and handling stress. Taken together, these results provide further evidence of a new type of circadian organisation in a teleost species where the eyes are required to sustain night time melatonin levels. Section: Regulatory systems

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“…One of the chemical supports of this oscillator is the nocturnal secretion of melatonin by photoreceptor cells. Melatonin is synthesized from serotonin (5-HT) through the successive enzymes serotonin (arylalkylamine) N-acetyltransferase (AANAT; EC 2.3.1.87) and hydroxyindole O-methyltransferase (HIOMT; EC 2.1.1.4), the activities of which have been demonstrated in the rat retina (Nagle et al 1973;Pang et al 1980;Reiter et al 1983). AANAT mRNA expression exhibits a circadian rhythm, and is localized to photoreceptor cells in rat retina (Niki et al 1998;Sakamoto and Ishida 1998).…”

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confidence: 99%

Serotonin synthesis and its light–dark variation in the rat retina

Chanut

Nguyen‐Legros²,

Labarthe

et al. 2002

Journal of Neurochemistry

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Retinal circadian rhythms are driven by an intrinsic oscillator, using chemical signals such as melatonin, secreted by photoreceptor cells. The purpose of the present work was to identify the origin of serotonin, the precursor of melatonin, in the retina of adult rat, where no immunoreactivity for serotonin or tryptophan hydroxylase had ever been detected. To demonstrate local synthesis of serotonin in the rat retina, substrates of tryptophan hydroxylase, the first limiting enzyme in the serotonin pathway, have been used. Tryptophan, in the presence of an inhibitor of aromatic amino acid decarboxylase, enhanced 5-hydroxytryptophan levels, whereas a-methyltryptophan, a competitive substrate inhibitor, was hydroxylated into a-methyl-5-hydroxytryptophan. Tryptophan hydroxylase substrate concentration was higher in the dark period than in the light period, and formation of hydroxylated compounds was increased. The presence of tryptophan hydroxylase mRNA in the rat retina was confirmed by RT-PCR. Taken together, the results support the local synthesis of serotonin by tryptophan hydroxylation, this metabolic pathway being required more critically when 5-HT is used for melatonin synthesis.

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Rhythms in immunoreactive melatonin in the retina and harderian gland of rats: Persistence after pinealectomy

Cited by 160 publications

References 24 publications

Retinal melatonin is metabolized within the eye of xenopus laevis.

Retinal melatonin is metabolized within the eye of xenopus laevis.

Retinal light input is required to sustain plasma melatonin rhythms in Nile tilapia Oreochromis niloticus niloticus

Serotonin synthesis and its light–dark variation in the rat retina

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