Use of 2-[125I]iodomelatonin to characterize melatonin binding sites in chicken retina.

Dubocovich, Margarita L.; Takahashi, Joseph S.

doi:10.1073/pnas.84.11.3916

Cited by 205 publications

(142 citation statements)

References 21 publications

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“…Melatonin, 2-iodomelatonin, and 6-chloromelatonin inhibited dopamine-stimulated CAMP accumulation, a well established response to Dl dopamine receptor activation in retina (Brown and Makman, 1972). The EC,, values for inhibition of dopamine-stimulated CAMP accumulation by melatonin and related agonists are similar to those for inhibition of chick retinal dopamine release (Dubocovich and Takahashi, 1987) and to the K, values for inhibition of 2-1251-iodomelatonin binding to chick brain slices (Siuciak et al, 1991) and retinal neurons (Iuvone and Gan, unpublished observation). The EC,, for inhibition of dopamine-stimulated CAMP accumulation by 2-iodomelatonin (35 PM) is virtually identical to the equilibrium dissociation constant (K,) for 2-Y-iodomelatonin binding to chick retinal neurons in culture (42 PM; Iuvone and Gan, 1994a).…”

Section: Discussionmentioning

confidence: 74%

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Functional interaction of melatonin receptors and D1 dopamine receptors in cultured chick retinal neurons

Iuvone

Gan

1995

J. Neurosci.

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The possible interaction of melatonin receptors and D1 dopamine receptors was investigated in neural cells prepared from embryonic day 8 chick retinas and cultured for 6 d. Dopamine stimulated cAMP accumulation in cultured retinal cells. This effect of dopamine was antagonized by addition of dopamine receptor antagonists (haloperidol and SCH23390) or melatonin receptor agonists (melatonin, 2- iodomelatonin, and 6-chloromelatonin). The inhibition of dopamine- stimulated cAMP accumulation by melatonin was concentration dependent, with half-maximal inhibition at approximately 160 pM. Melatonin inhibited the effect of dopamine at all dopamine concentrations, suppressing the maximal response to the neurotransmitter by approximately 70%. Melatonin also inhibited the stimulation of cAMP accumulation by SKF 82958, a selective D1 dopamine receptor agonist. Pretreatment of cultures with pertussis toxin had no significant effect on dopamine-stimulated cAMP accumulation, but inhibited the response to melatonin. In contrast to its effect on cAMP accumulation, melatonin had no effect on dopamine-stimulated inositol phosphate accumulation. These results suggest that melatonin receptors are coupled to dopamine receptor-regulated adenylate cyclase via an inhibitory G protein, and demonstrate another mechanism, in addition to inhibition of dopamine release, through which melatonin can modulate dopaminergic neurotransmission.

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Section: Discussionmentioning

confidence: 74%

“…High-affinity melatonin receptors have been characterized in retina using 2-1Z51-iodomelatonin as a radioligand (e.g., Dubocovich and Takahashi, 1987;Laitinen and Saavedra, 1990;Wiechmann and Wirsig-Wiechmann, 1991). Occupation of melatonin receptors in retinal membranes inhibits forskolin-stimulated adenylate cyclase (Niles et al, 1991).…”

mentioning

confidence: 99%

Functional interaction of melatonin receptors and D1 dopamine receptors in cultured chick retinal neurons

Iuvone

Gan

1995

J. Neurosci.

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“…In addition to the pineal gland, MEL is synthesized in several other structures (retina, Harderian gland, gut) where the genetic expression and biochemical activity of the MEL-synthesizing enzymes have been detected (Quay, 1965;Cardinali and Wurtman, 1972;Quay and Ma, 1976;Brammer et al, 1978;Pévet et al, 1980a;Vivien-Roels et al, 1981;Gauer and Craft, 1996;Roseboom et al, 1996;Ribelayga et al, 1998a;Djéridane et al, 1998Djéridane et al, , 2000. Since following pinealectomy the plasma MEL concentration is very low and since some of these structures contain MEL-R (Dubocovich and Takahashi, 1987;Lopez-Gonzalez et al, 1991), it has been proposed that MEL plays an auto/paracrine role in these structures.…”

Section: Other Roles Of Melatoninmentioning

confidence: 99%

Generation of the Melatonin Endocrine Message in Mammals: A Review of the Complex Regulation of Melatonin Synthesis by Norepinephrine, Peptides, and Other Pineal Transmitters

2003

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“…Melatonin administration increases the degree of photoreceptor cell death in response to environmental light exposure, but is also involved in the regulation of necessary circadian events that occur in the retina, such as photoreceptor outer segment disk shedding and phagocytosis (Besharse and Dunis, 1983;White and Fisher, 1989), modulation of dopamine release (Dubocovich, 1983;Dubocovich and Takahashi, 1987), and increased sensitivity of the retina to light (Wiechmann et al, 1988(Wiechmann et al, , 2003. Melatonin also delays photoreceptor degeneration in a dystrophic animal model (Liang et al, 2001).…”

Section: Discussionmentioning

confidence: 99%

“…Although signals from the inner retina undoubtedly play a major role in the circadian activities of retinal photoreceptors (Boatright et al, 1994;Dubocovich, 1983;Dubocovich and Takahashi, 1987), intracrine (autocrine) melatonin signaling in photoreceptors likely contributes substantially to circadian regulation in the retina.…”

Section: Introductionmentioning

confidence: 99%

Influence of dietary melatonin on photoreceptor survival in the rat retina: An ocular toxicity study

Wiechmann

Chignell

Roberts

2008

Experimental Eye Research

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Previous studies have shown that melatonin treatment increases the susceptibility of retinal photoreceptors to light-induced cell death. The purpose of this study was to evaluate under various conditions the potential toxicity of dietary melatonin on retinal photoreceptors. Male and female Fischer 344 (non-pigmented) and Long-Evans (pigmented) rats were treated with daily single doses of melatonin by gavage for a period of 14 days early in the light period or early in the dark period. In another group, rats were treated 3 times per week with melatonin early in the light period, and then exposed to high intensity illumination (1,000 −1,500 lux; HII) for two hours, and then returned to the normal cyclic lighting regime. At the end of the treatment periods, morphometric measurements of outer nuclear layer thickness (ONL; the layer containing the photoreceptors cell nuclei) were made at specific loci throughout the retinas. In male and female non-pigmented Fischer rats, melatonin administration increased the degree of photoreceptor cell death when administered during the nighttime and during the day when followed by exposure to HII. There were some modest effects of melatonin on photoreceptor cell death when administered to Fisher rats during the day or night without exposure to HII. Melatonin treatment caused increases in the degree of photoreceptor cell death when administered in the night to male pigmented Long-Evans rats, but melatonin administration during the day, either with or without exposure to HII, had little if any effect on photoreceptor cell survival. In pigmented female Long Evans rats, melatonin administration did not appear to have significant effects on photoreceptor cell death in any treatment group. The results of this study confirm and extend previous reports that melatonin increases the susceptibility of photoreceptors to light-induced cell death in non-pigmented rats. It further suggests that during the dark period, melatonin administration alone (i.e., no HII exposure) to pigmented male rats may have a toxic effect on retinal cells. These results suggest that dietary melatonin, in combination with a brief exposure to high intensity illumination, induces cellular disruption in a small number of photoreceptors. Chronic exposure to natural or artificial light and simultaneous intake of melatonin may potentially contribute to a significant loss of photoreceptor cells in the aging retina.

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Use of 2-[125I]iodomelatonin to characterize melatonin binding sites in chicken retina.

Cited by 205 publications

References 21 publications

Functional interaction of melatonin receptors and D1 dopamine receptors in cultured chick retinal neurons

Functional interaction of melatonin receptors and D1 dopamine receptors in cultured chick retinal neurons

Generation of the Melatonin Endocrine Message in Mammals: A Review of the Complex Regulation of Melatonin Synthesis by Norepinephrine, Peptides, and Other Pineal Transmitters

Influence of dietary melatonin on photoreceptor survival in the rat retina: An ocular toxicity study

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