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Nisembaum LG, Loentgen G, L’Honoré T, Martin P, Paulin CH, Fuentès M, Escoubeyrou K, Delgado MJ, Besseau L, Falcón J. Transient Receptor Potential-Vanilloid (TRPV1-TRPV4) Channels in the Atlantic Salmon, Salmo salar. A Focus on the Pineal Gland and Melatonin Production. Front Physiol 2022; 12:784416. [PMID: 35069244 PMCID: PMC8782258 DOI: 10.3389/fphys.2021.784416] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 12/07/2021] [Indexed: 11/13/2022] Open
Abstract
Fish are ectotherm, which rely on the external temperature to regulate their internal body temperature, although some may perform partial endothermy. Together with photoperiod, temperature oscillations, contribute to synchronizing the daily and seasonal variations of fish metabolism, physiology and behavior. Recent studies are shedding light on the mechanisms of temperature sensing and behavioral thermoregulation in fish. In particular, the role of some members of the transient receptor potential channels (TRP) is being gradually unraveled. The present study in the migratory Atlantic salmon, Salmo salar, aims at identifying the tissue distribution and abundance in mRNA corresponding to the TRP of the vanilloid subfamilies, TRPV1 and TRPV4, and at characterizing their putative role in the control of the temperature-dependent modulation of melatonin production-the time-keeping hormone-by the pineal gland. In Salmo salar, TRPV1 and TRPV4 mRNA tissue distribution appeared ubiquitous; mRNA abundance varied as a function of the month investigated. In situ hybridization and immunohistochemistry indicated specific labeling located in the photoreceptor cells of the pineal gland and the retina. Additionally, TRPV analogs modulated the production of melatonin by isolated pineal glands in culture. The TRPV1 agonist induced an inhibitory response at high concentrations, while evoking a bell-shaped response (stimulatory at low, and inhibitory at high, concentrations) when added with an antagonist. The TRPV4 agonist was stimulatory at the highest concentration used. Altogether, the present results agree with the known widespread distribution and role of TRPV1 and TRPV4 channels, and with published data on trout (Oncorhynchus mykiss), leading to suggest these channels mediate the effects of temperature on S. salar pineal melatonin production. We discuss their involvement in controlling the timing of daily and seasonal events in this migratory species, in the context of an increasing warming of water temperatures.
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Affiliation(s)
- Laura Gabriela Nisembaum
- Sorbonne Université (SU), CNRS, Biologie Intégrative des Organismes Marins (BIOM), Banyuls-sur-Mer, France
| | - Guillaume Loentgen
- Sorbonne Université (SU), CNRS, Biologie Intégrative des Organismes Marins (BIOM), Banyuls-sur-Mer, France
| | - Thibaut L’Honoré
- Sorbonne Université (SU), CNRS, Biologie Intégrative des Organismes Marins (BIOM), Banyuls-sur-Mer, France
| | - Patrick Martin
- Conservatoire National du Saumon Sauvage, Chanteuges, France
| | - Charles-Hubert Paulin
- Sorbonne Université (SU), CNRS, Biologie Intégrative des Organismes Marins (BIOM), Banyuls-sur-Mer, France
| | - Michael Fuentès
- Sorbonne Université (SU), CNRS, Biologie Intégrative des Organismes Marins (BIOM), Banyuls-sur-Mer, France
| | - Karine Escoubeyrou
- SU, CNRS Fédération 3724, Observatoire Océanologique, Banyuls-sur-Mer, France
| | - María Jesús Delgado
- Departamento de Genética, Fisiología y Microbiologia, Facultad de Biología, Universidad Complutense de Madrid, Madrid, Spain
| | - Laurence Besseau
- Sorbonne Université (SU), CNRS, Biologie Intégrative des Organismes Marins (BIOM), Banyuls-sur-Mer, France
| | - Jack Falcón
- Sorbonne Université (SU), CNRS, Biologie Intégrative des Organismes Marins (BIOM), Banyuls-sur-Mer, France
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Sánchez-Vázquez FJ, López-Olmeda JF, Vera LM, Migaud H, López-Patiño MA, Míguez JM. Environmental Cycles, Melatonin, and Circadian Control of Stress Response in Fish. Front Endocrinol (Lausanne) 2019; 10:279. [PMID: 31244768 PMCID: PMC6579845 DOI: 10.3389/fendo.2019.00279] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 04/16/2019] [Indexed: 01/10/2023] Open
Abstract
Fish have evolved a biological clock to cope with environmental cycles, so they display circadian rhythms in most physiological functions including stress response. Photoperiodic information is transduced by the pineal organ into a rhythmic secretion of melatonin, which is released into the blood circulation with high concentrations at night and low during the day. The melatonin rhythmic profile is under the control of circadian clocks in most fish (except salmonids), and it is considered as an important output of the circadian system, thus modulating most daily behavioral and physiological rhythms. Lighting conditions (intensity and spectrum) change in the underwater environment and affect fish embryo and larvae development: constant light/darkness or red lights can lead to increased malformations and mortality, whereas blue light usually results in best hatching rates and growth performance in marine fish. Many factors display daily rhythms along the hypothalamus-pituitary-interrenal (HPI) axis that controls stress response in fish, including corticotropin-releasing hormone (Crh) and its binding protein (Crhbp), proopiomelanocortin A and B (Pomca and Pomcb), and plasma cortisol, glucose, and lactate. Many of these circadian rhythms are under the control of endogenous molecular clocks, which consist of self-sustained transcriptional-translational feedback loops involving the cyclic expression of circadian clock genes (clock, bmal, per, and cry) which persists under constant light or darkness. Exposing fish to a stressor can result in altered rhythms of most stress indicators, such as cortisol, glucose, and lactate among others, as well as daily rhythms of most behavioral and physiological functions. In addition, crh and pomca expression profiles can be affected by other factors such as light spectrum, which strongly influence the expression profile of growth-related (igf1a, igf2a) genes. Additionally, the daily cycle of water temperature (warmer at day and cooler at night) is another factor that has to be considered. The response to any acute stressor is not only species dependent, but also depends on the time of the day when the stress occurs: nocturnal species show higher responses when stressed during day time, whereas diurnal fish respond stronger at night. Melatonin administration in fish has sedative effects with a reduction in locomotor activity and cortisol levels, as well as reduced liver glycogen and dopaminergic and serotonergic activities within the hypothalamus. In this paper, we are reviewing the role of environmental cycles and biological clocks on the entrainment of daily rhythms in the HPI axis and stress responses in fish.
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Affiliation(s)
| | | | - Luisa Maria Vera
- Institute of Aquaculture, University of Stirling, Stirling, United Kingdom
| | - Herve Migaud
- Institute of Aquaculture, University of Stirling, Stirling, United Kingdom
| | - Marcos Antonio López-Patiño
- Laboratory Animal Physiology, Department Biology and Health Science, Faculty of Biology and Centro Singular de Investigación Mariña-ECIMAT, University of Vigo, Vigo, Spain
| | - Jesús M. Míguez
- Laboratory Animal Physiology, Department Biology and Health Science, Faculty of Biology and Centro Singular de Investigación Mariña-ECIMAT, University of Vigo, Vigo, Spain
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Nisembaum LG, Besseau L, Paulin CH, Charpantier A, Martin P, Magnanou E, Fuentès M, Delgado MJ, Falcón J. In the Heat of the Night: Thermo-TRPV Channels in the Salmonid Pineal Photoreceptors and Modulation of Melatonin Secretion. Endocrinology 2015; 156:4629-38. [PMID: 26389691 DOI: 10.1210/en.2015-1684] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Photoperiod plays an essential role in the synchronization of metabolism, physiology, and behavior to the cyclic variations of the environment. In vertebrates, information is relayed by the pineal cells and translated into the nocturnal production of melatonin. The duration of this signal corresponds to the duration of the night. In fish, the pinealocytes are true photoreceptors in which the amplitude of the nocturnal surge is modulated by temperature in a species-dependent manner. Thus, the daily and annual variations in the amplitude and duration of the nocturnal melatonin signal provide information on daily and calendar time. Both light and temperature act on the activity of the penultimate enzyme in the melatonin biosynthesis pathway, the arylalkylamine N-acetyltransferase (serotonin → N-acetylserotonin). Although the mechanisms of the light/dark regulation of melatonin secretion are quite well understood, those of temperature remain unelucidated. More generally, the mechanisms of thermoreception are unknown in ectotherms. Here we provide the first evidence that two thermotransient receptor potential (TRP) channels, TRPV1 and TRPV4, are expressed in the pineal photoreceptor cells of a teleost fish, in which they modulate melatonin secretion in vitro. The effects are temperature dependent, at least for TRPV1. Our data support the idea that the pineal of fish is involved in thermoregulation and that the pineal photoreceptors are also thermoreceptors. In other nervous and nonnervous tissues, TRPV1 and TRPV4 display a ubiquitous but quantitatively variable distribution. These results are a fundamental step in the elucidation of the mechanisms of temperature transduction in fish.
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Affiliation(s)
- Laura Gabriela Nisembaum
- Sorbonne Universités, Université Pierre et Marie Curie, Paris 06 (L.B., C.-H.P., A.C.), Centre National de la Recherche Scientifique (L.G.N., E.M., M.F., J.F.), Biologie Intégrative des Organismes Marins (BIOM), Observatoire Océanologique, F-66650 Banyuls sur Mer, France; Conservatoire National du Saumon Sauvage (P.M.), F-43300 Chanteuges, France; and Universidad Complutense de Madrid (L.G.N., M.J.D.) E-28040 Madrid, Spain
| | - Laurence Besseau
- Sorbonne Universités, Université Pierre et Marie Curie, Paris 06 (L.B., C.-H.P., A.C.), Centre National de la Recherche Scientifique (L.G.N., E.M., M.F., J.F.), Biologie Intégrative des Organismes Marins (BIOM), Observatoire Océanologique, F-66650 Banyuls sur Mer, France; Conservatoire National du Saumon Sauvage (P.M.), F-43300 Chanteuges, France; and Universidad Complutense de Madrid (L.G.N., M.J.D.) E-28040 Madrid, Spain
| | - Charles-Hubert Paulin
- Sorbonne Universités, Université Pierre et Marie Curie, Paris 06 (L.B., C.-H.P., A.C.), Centre National de la Recherche Scientifique (L.G.N., E.M., M.F., J.F.), Biologie Intégrative des Organismes Marins (BIOM), Observatoire Océanologique, F-66650 Banyuls sur Mer, France; Conservatoire National du Saumon Sauvage (P.M.), F-43300 Chanteuges, France; and Universidad Complutense de Madrid (L.G.N., M.J.D.) E-28040 Madrid, Spain
| | - Alice Charpantier
- Sorbonne Universités, Université Pierre et Marie Curie, Paris 06 (L.B., C.-H.P., A.C.), Centre National de la Recherche Scientifique (L.G.N., E.M., M.F., J.F.), Biologie Intégrative des Organismes Marins (BIOM), Observatoire Océanologique, F-66650 Banyuls sur Mer, France; Conservatoire National du Saumon Sauvage (P.M.), F-43300 Chanteuges, France; and Universidad Complutense de Madrid (L.G.N., M.J.D.) E-28040 Madrid, Spain
| | - Patrick Martin
- Sorbonne Universités, Université Pierre et Marie Curie, Paris 06 (L.B., C.-H.P., A.C.), Centre National de la Recherche Scientifique (L.G.N., E.M., M.F., J.F.), Biologie Intégrative des Organismes Marins (BIOM), Observatoire Océanologique, F-66650 Banyuls sur Mer, France; Conservatoire National du Saumon Sauvage (P.M.), F-43300 Chanteuges, France; and Universidad Complutense de Madrid (L.G.N., M.J.D.) E-28040 Madrid, Spain
| | - Elodie Magnanou
- Sorbonne Universités, Université Pierre et Marie Curie, Paris 06 (L.B., C.-H.P., A.C.), Centre National de la Recherche Scientifique (L.G.N., E.M., M.F., J.F.), Biologie Intégrative des Organismes Marins (BIOM), Observatoire Océanologique, F-66650 Banyuls sur Mer, France; Conservatoire National du Saumon Sauvage (P.M.), F-43300 Chanteuges, France; and Universidad Complutense de Madrid (L.G.N., M.J.D.) E-28040 Madrid, Spain
| | - Michael Fuentès
- Sorbonne Universités, Université Pierre et Marie Curie, Paris 06 (L.B., C.-H.P., A.C.), Centre National de la Recherche Scientifique (L.G.N., E.M., M.F., J.F.), Biologie Intégrative des Organismes Marins (BIOM), Observatoire Océanologique, F-66650 Banyuls sur Mer, France; Conservatoire National du Saumon Sauvage (P.M.), F-43300 Chanteuges, France; and Universidad Complutense de Madrid (L.G.N., M.J.D.) E-28040 Madrid, Spain
| | - Maria-Jesus Delgado
- Sorbonne Universités, Université Pierre et Marie Curie, Paris 06 (L.B., C.-H.P., A.C.), Centre National de la Recherche Scientifique (L.G.N., E.M., M.F., J.F.), Biologie Intégrative des Organismes Marins (BIOM), Observatoire Océanologique, F-66650 Banyuls sur Mer, France; Conservatoire National du Saumon Sauvage (P.M.), F-43300 Chanteuges, France; and Universidad Complutense de Madrid (L.G.N., M.J.D.) E-28040 Madrid, Spain
| | - Jack Falcón
- Sorbonne Universités, Université Pierre et Marie Curie, Paris 06 (L.B., C.-H.P., A.C.), Centre National de la Recherche Scientifique (L.G.N., E.M., M.F., J.F.), Biologie Intégrative des Organismes Marins (BIOM), Observatoire Océanologique, F-66650 Banyuls sur Mer, France; Conservatoire National du Saumon Sauvage (P.M.), F-43300 Chanteuges, France; and Universidad Complutense de Madrid (L.G.N., M.J.D.) E-28040 Madrid, Spain
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Ceinos RM, Polakof S, Illamola AR, Soengas JL, Míguez JM. Food deprivation and refeeding effects on pineal indoles metabolism and melatonin synthesis in the rainbow trout Oncorhynchus mykiss. Gen Comp Endocrinol 2008; 156:410-7. [PMID: 18275959 DOI: 10.1016/j.ygcen.2008.01.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2007] [Revised: 12/27/2007] [Accepted: 01/02/2008] [Indexed: 11/27/2022]
Abstract
The effects of food deprivation and refeeding on daily rhythms of serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA) and melatonin contents, as well as on arylalkylamine N-acetyltransferase (AANAT) activity were evaluated in the pineal organ of rainbow trout. In addition, changes in circulating melatonin and cortisol levels were tested at one single point at day and night. Immature rainbow trout were distributed in 3 experimental groups: fish fed, fish fasted (7 days), and fish fasted for 7 days and refed for 5 days. All fish were sampled from each treatment group at different times of the day-night cycle. Pineal melatonin levels and AANAT activity showed daily variations in either fed, fasted and refed trout, displaying highest values at night. Fasted trout showed reduced melatonin content throughout the 24-h cycle, which was associated with decreased AANAT activity. Rhythms of pineal 5-HT and 5-HIAA levels were evident in all groups and were negatively correlated to melatonin in fed fish groups, but not in fasted fish. A higher content of 5-HT and 5-HIAA was observed in fasted fish during the night with no apparent changes during daytime for 5-HT and increased 5-HIAA levels. Furthermore, decreased circulating levels of melatonin were observed at midday, but not at night, in food deprived trout. Refeeding for 5 days generally counteracted the effects of food deprivation. Cortisol levels in plasma were reduced after food deprivation and remained low in refed fish. The results show that food deprivation impairs daily rhythms of melatonin content in trout pineal organ by affecting the activity of melatonin synthesizing enzymes rather than by a deficiency in substrate availability.
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Affiliation(s)
- Rosa M Ceinos
- Departamento de Bioloxía Funcional e Ciencias da Saude, Edificio de Ciencias Experimentais, Facultade de Bioloxía, Universidade de Vigo, Vigo, Pontevedra, Spain
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5
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Molecular and Cellular Regulation of Pineal Organ Responses. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/s1546-5098(06)25006-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Ceinos RM, Rábade S, Soengas JL, Míguez JM. Indoleamines and 5-methoxyindoles in trout pineal organ in vivo: daily changes and influence of photoperiod. Gen Comp Endocrinol 2005; 144:67-77. [PMID: 15950974 DOI: 10.1016/j.ygcen.2005.04.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2004] [Revised: 04/15/2005] [Accepted: 04/25/2005] [Indexed: 10/25/2022]
Abstract
This study describes the diel rhythms in several indoleamines, melatonin, and related 5-methoxyindoles in the pineal organ of rainbow trout in vivo. In addition, the effect of different photoperiod conditions was evaluated. Melatonin levels displayed clear daily rhythms in the pineal organ of rainbow trout kept experimentally under long (LD 16:08), neutral (LD 12:12), and short (LD 08:16) photoperiods. Duration of melatonin signal was dependent on the night length of prevailing photoperiod, while peak amplitude was higher when lengthening the photoperiod. Significant daily rhythms in 5-HT content, the precursor of melatonin synthesis, were found in neutral and short photoperiod with increases of the amine content just after the light-dark interphase and decreases in the middle of the night, which were more important under short photoperiod. In contrast, no significant 24-h cyclic variation was found in pineal 5-HT content under long photoperiod. Daily profiles in the content of the main 5-HT oxidative metabolite, the 5-hydroxyindoleacetic acid (5-HIAA), outlined those of the amine precursor. The chronograms of both aminergic compounds contrast with those of 5-hydroxytryptophan content, which displayed a net tendency to increase at night. This study also provides evidence for the existence of daily cyclic changes in the content of 5-methoxytryptamine (5-MT), 5-methoxyindoleacetic acid (5-MIAA), and 5-methoxytryptophol (5-MTOL) in trout pineal organ, which were also dependent on photoperiod. The 24-h profiles in 5-MT content correlated well with those of 5-HT, showing a peak at the first hour of darkness in all photoperiodic conditions, and a decay at midnight only in both neutral and long photoperiods. Similarly, the content of 5-MTOL also displayed high values during the day-night transition in trout kept under neutral and long photoperiods, followed by a slow decay all along the night. Finally, levels of 5-MIAA increased in all photoperiods when lights were turned off, being this nocturnal increase maximal in fish kept under LD 16:08. These results suggest that light-dark cycle modulates daily rhythms in pineal indoles and non-melatonin 5-methoxyindoles by acting mainly through the melatonin synthesis activity, which limits the availability of 5-HT for the oxidative and direct methylation pathways. In addition, it seems that a nocturnally increased synthesis of 5-HT might be a requirement for the optimal formation of melatonin and other 5-methoxyindoles in the pineal organ when trout remain under short photoperiods.
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Affiliation(s)
- Rosa M Ceinos
- Laboratorio de Fisiología Animal, Departamento Biología Funcional y CC Salud, Facultad de Biología, Universidad de Vigo, 36200 Vigo, Spain
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Benyassi A, Schwartz C, Ducouret B, Falcón J. Glucocorticoid receptors and serotonin N-acetyltransferase activity in the fish pineal organ. Neuroreport 2001; 12:889-92. [PMID: 11303753 DOI: 10.1097/00001756-200104170-00004] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
This study aimed to determine whether glucocorticoid receptors are expressed in the photosensitive trout pineal organ, and whether glucocorticoids modulate melatonin secretion. On Western blots from pineal extracts, an antibody directed against trout glucocorticoid receptor labeled a single band at the expected size (approximately 100 kDa). Dexamethasone inhibited pineal arylalkylamine N-acetyltransferase activity (AANAT2; serotonin --> N-acetylserotonin) in a dose-dependent manner after 6 h of culture in the dark (IC50 2.10(-8) M). RU486 (10(-7) M) alone had a partial agonistic activity, whereas it antagonized the effects of 10(-8) M dexamethasone. Hydroxyindole-O-methyltransferase activity (N-acetylserotonin --> melatonin) remained unaffected. This is the first demonstration that glucocorticoid receptors are present in the pineal organ and that glucocorticoids modulate melatonin production.
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Affiliation(s)
- A Benyassi
- Faculté des Sciences de Fés, Laboratoire de Physiologie Animale, Morocco
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8
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Abstract
Daily rhythms are a fundamental feature of all living organisms; most are synchronized by the 24 hr light/dark (LD) cycle. In most species, these rhythms are generated by a circadian system, and free run under constant conditions with a period close to 24 hr. To function properly the system needs a pacemaker or clock, an entrainment pathway to the clock, and one or more output signals. In vertebrates, the pineal hormone melatonin is one of these signals which functions as an internal time-keeping molecule. Its production is high at night and low during day. Evidence indicates that each melatonin producing cell of the pineal constitutes a circadian system per se in non-mammalian vertebrates. In addition to the melatonin generating system, they contain the clock as well as the photoreceptive unit. This is despite the fact that these cells have been profoundly modified from fish to birds. Modifications include a regression of the photoreceptive capacities, and of the ability to transmit a nervous message to the brain. The ultimate stage of this evolutionary process leads to the definitive loss of both the direct photosensitivity and the clock, as observed in the pineal of mammals. This review focuses on the functional properties of the cellular circadian clocks of non-mammalian vertebrates. How functions the clock? How is the photoreceptive unit linked to it and how is the clock linked to its output signal? These questions are addressed in light of past and recent data obtained in vertebrates, as well as invertebrates and unicellulars.
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Affiliation(s)
- J Falcón
- CNRS UMR 6558, Département des Neurosciences, Université de Poitiers, France.
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Okimoto DK, Stetson MH. Properties of the melatonin-generating system of the sailfin molly, Poecilia velifera. Gen Comp Endocrinol 1999; 114:293-303. [PMID: 10208778 DOI: 10.1006/gcen.1999.7258] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The properties of the melatonin-generating system of a tropical teleost, the sailfin molly (Poecilia velifera), were investigated in vitro in a series of experiments using static or perifusion culture techniques. The properties examined included photic entrainment, circadian rhythmicity under continuous light (LL) and continuous darkness (DD), functionality of the melatonin-generating system at birth, and presence of multiple circadian oscillators in the molly pineal. Pineal glands or skull caps with the pineal gland firmly attached were dissected from adult and new-born fishes, respectively, and placed into static or perifusion culture at constant temperature (27 degrees C) depending upon the experiment. Melatonin release in samples was quantified by RIA. Rhythmic melatonin release was observed from isolated adult pineals under 12L:12D and 14L:10D, with low amounts of melatonin released during the light and high amounts during the dark. Melatonin release was inhibited by LL. However, under DD, melatonin release was robust and rhythmic with a circadian period (Tau) that ranged between 21.3 and 27.0 h (n = 21). Pineals from new-born (1-day old) mollies released melatonin rhythmically under a light:dark cycle and DD in both static and perifusion culture. Melatonin release from half and quarter pineals of adult mollies under DD was robust and rhythmic with circadian periods that ranged between 22.5 and 29.0 h (n = 19). Taken together, these data show that the molly pineal is photosensitive, fully functional from birth, and contains multiple circadian oscillators (at least four) regulating melatonin production.
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Affiliation(s)
- D K Okimoto
- Department of Biological Sciences, University of Delaware, Newark, Delaware, 19716, USA
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Okimoto DK, Stetson MH. Presence of an intrapineal circadian oscillator in the teleostean family Poeciliidae. Gen Comp Endocrinol 1999; 114:304-12. [PMID: 10208779 DOI: 10.1006/gcen.1999.7260] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In most fish, rhythmic melatonin production is controlled by circadian oscillators located within the pineal (=pineal clocks) that are reset daily by the ambient light:dark (LD) cycle. However, one question that has yet to be addressed concerns the phylogenetic distribution of the pineal clock within fish families. We tested whether a pineal clock identified in the sailfin molly (Poecilia velifera) in an earlier study is also present in some other representatives of the teleostean family Poeciliidae. Isolated pineals from adults belonging to the genus Poecilia (P. velifera albino, P. reticulata, and P. sphenops), genus Xiphophorus (X. helleri and X. maculatus), and genus Limia (L. vittata) were obtained and cultured under LD and/or continuous darkness (DD) at constant temperature (27 degrees C). With one exception, free-running rhythms in melatonin release with circadian periodicities ranging from 19.5 to 27.4 h (n = 26) were detected in isolated pineals from all poeciliid representatives tested under DD exposure. In addition, rhythmic melatonin production was also observed in isolated pineals of some representatives tested from all three genera under LD exposure, suggesting the property of direct photosensitivity. Taken together, these data suggest that a circadian oscillator residing in the pineal of the sailfin molly also appears to be present in all of the poeciliid representatives tested in our system, supporting the notion that the presence of a pineal clock occurs at the family level of taxonomic organization.
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Affiliation(s)
- D K Okimoto
- Department of Biological Sciences, University of Delaware, Newark, Delaware, 19716, USA
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Bolliet V, Bégay V, Taragnat C, Ravault JP, Collin JP, Falcón J. Photoreceptor cells of the pike pineal organ as cellular circadian oscillators. Eur J Neurosci 1997; 9:643-53. [PMID: 9153571 DOI: 10.1111/j.1460-9568.1997.tb01413.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In the pike pineal, the rhythm of melatonin (MEL) secretion is driven by a population of cellular circadian oscillators, synchronized by the 24 h light/dark (LD) cycle. Because the pineal photoreceptor contains both the input and output pathways of the clock, this cell is likely to be a cellular circadian system by itself. To support this idea, we have dissociated and cultured pike pineal cells as well as purified photoreceptors. In culture, the pineal cells reassociated in follicles, surrounded by collagen fibres. At the electron microscopic level, they appeared well preserved. Total cells consisted mainly of photoreceptors and glia. Purified cells corresponded exclusively to photoreceptors. Under LD, MEL production was rhythmic. Under constant darkness (DD), the rhythm was well sustained for at least six 24 h cycles (tau = 24/27 h) with 1 x 10(6) total cells/well or below; with 2 x 10(6) total cells/well, a strong damping occurred towards high levels as soon as after the second cycle. At the density of 0.5 x 10(6) cells/well, purified photoreceptors produced less MEL than an equivalent amount of total cells. However, the pattern of the oscillations was similar to that observed with 2 x 10(6) total cells, i.e. a damping occurred rapidly. Decreasing the density to 0.125 x 10(6) photoreceptors/well resulted in a loss of homogeneity among replicates. The production of melatonin by single photoreceptors was monitored by means of the reverse haemolytic plaque assay. Both under LD and under DD, the number of photoreceptors releasing melatonin was higher during the (subjective) dark than during the (subjective) light. The results provide strong support to the idea that the pike pineal photoreceptor is a cellular circadian system. Expression of the oscillations seemed to depend on several factors, including cell to cell contacts between photoreceptors. There is indication that also MEL and glia might be involved.
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Affiliation(s)
- V Bolliet
- Laboratoire de Neurobiologie et Neuroendocrinologie Cellulaires, UMR CNRS 6558, Université de Poitiers, France
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Falcón J, Van Camp G, Collin JP. Adenosine A2 receptor-mediated stimulation of cyclic AMP in cultured chicken pineal cells. J Pineal Res 1995; 19:72-8. [PMID: 8609599 DOI: 10.1111/j.1600-079x.1995.tb00173.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The pineal gland of vertebrates produces the time-keeping hormone melatonin in a rhythmic manner. Regulation of melatonin production is a multifactorial process. In the chicken, light, perceived through the skull, and norepinephrine, acting through alpha 2-adrenergic receptors, synergistically inhibit day time melatonin production. In addition, adenosine exerts autocrine/paracrine modulatory effects on melatonin secretion. In an attempt to elucidate how these effects of adenosine are mediated, chicken pineal cells were cultured, in the dark during day time, in the presence of different analogs of adenosine. When the adenosine transmembranous carrier was inhibited, chloroadenosine stimulated cyclic AMP (cAMP) accumulation in a time- and dose-dependent manner. The effects were antagonized by 8-phenyltheophylline, an antagonist at the A1/A2 adenosine receptors. A dose-dependent stimulation of cAMP accumulation was also obtained with other adenosine agonists, with the following order of potency: N-ethylcarboxamidoadenosine > cyclopentyladenosine > R-phenyl-isopropylade-nosine. The stimulatory effect of the latter compound was still observed when basal cAMP levels were increased in the presence of forskolin. Under our experimental conditions no inhibition of cAMP content was observed. Our results are consistent with the idea that stimulation of melatonin secretion by adenosine analogs is mediated through A2 receptors.
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Affiliation(s)
- J Falcón
- Departement des neurosciences de l'URA CNRS No. 1869, UFR Sciences, Poitiers, France
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13
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Bégay V, Bois P, Collin JP, Lenfant J, Falcón J. Calcium and melatonin production in dissociated trout pineal photoreceptor cells in culture. Cell Calcium 1994; 16:37-46. [PMID: 7525073 DOI: 10.1016/s0143-4160(05)80006-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Trout pineal cells maintained in primary culture produce melatonin in high amounts during night time and low amounts during daytime. The dark-induced increase in melatonin production was enhanced, in a dose-dependent manner, by elevating extracellular calcium concentration. Low external calcium concentration reduced nocturnal and diurnal melatonin production. Bay K 8644 increased, in a dose-dependent manner, the dark-induced rise in melatonin output, and this effect was antagonized by nifedipine and verapamil. This suggests a role for the dihydropyridine calcium channels in the regulation of the melatonin output. To confirm this, patch-clamp recordings (whole-cell perforated) were run in a 20 mmol/l barium medium at different holding potentials from -80 mV. A voltage-dependent inward current was activated from -30 mV to +40 mV with a maximal amplitude being observed at 0 mV. This current was drastically increased in the presence of Bay K 8644. Nifedipine inhibited the current both in the absence or in the presence of Bay K 8644. Our results are consistent with the idea that extracellular calcium participates in the control of melatonin secretion by photoreceptor cells. It is suggested that activation of the voltage-dependent L-type channel may modulate this secretion.
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Affiliation(s)
- V Bégay
- Laboratoire de Neurobiologie et de Neuroendocrinologie Cellulaires, URA CNRS 1869, Poitiers, France
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14
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Lipid composition of the pineal organ from rainbow trout (Oncorhynchus mykiss). Lipids 1994; 29:311-7. [DOI: 10.1007/bf02537183] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/1993] [Revised: 03/23/1994] [Accepted: 03/23/1994] [Indexed: 01/30/2023]
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Bolliet V, Bégay V, Ravault JP, Ali MA, Collin JP, Falcón J. Multiple circadian oscillators in the photosensitive pike pineal gland: a study using organ and cell culture. J Pineal Res 1994; 16:77-84. [PMID: 8014827 DOI: 10.1111/j.1600-079x.1994.tb00086.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The fish pineal organ contains typical and, in some species, modified photoreceptor cells involved in the photoperiodic control of melatonin production. In the majority of species studied, the rhythm in melatonin production is driven by an intra-pineal circadian oscillator synchronized by the light:dark cycle. In the present study, it is shown that the endogenous rhythm in melatonin release of superfused pike pineals maintained under constant darkness is expressed at temperatures of 19 degrees C, 20 degrees C, 25 degrees C, and 30 degrees C (period > 24 hr), but not at temperatures of 10 degrees C and 15 degrees C. Under constant darkness, pineal fractions containing either typical photoreceptors, modified photoreceptors, or both behaved like total organs. Dissociated pike pineal cells, cultured statically at 20 degrees C, expressed a high amplitude rhythm in melatonin secretion under a light:dark cycle. Under constant darkness, circadian oscillations, which appeared better sustained than in organ culture, were also observed. This study provides the first evidence that the rhythmic production of melatonin, by a fish pineal, is driven by a population of circadian oscillators or clocks. It is hypothesized that each typical and modified photoreceptor might be the locus of a circadian clock. Damping of the overall rhythm under constant darkness might reflect the desynchronization (uncoupling) between these clocks and/or damping of individual oscillators.
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Affiliation(s)
- V Bolliet
- Laboratoire de Neurobiologie et Neuroendocrinologie Cellulaires, URA CNRS 290, Université de Poitiers, France
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Thibault C, Falcón J, Greenhouse SS, Lowery CA, Gern WA, Collin JP. Regulation of melatonin production by pineal photoreceptor cells: role of cyclic nucleotides in the trout (Oncorhynchus mykiss). J Neurochem 1993; 61:332-9. [PMID: 8390563 DOI: 10.1111/j.1471-4159.1993.tb03572.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The light/dark cycle influences the rhythmic production of melatonin by the trout pineal organ through a modulation of the serotonin N-acetyltransferase (NAT) activity. In static organ culture, cyclic AMP (cAMP) levels (in darkness) and NAT activity (in darkness or light) were stimulated in the presence of forskolin, isobutylmethylxanthine, or theophylline. Analogues of cAMP, but not of cyclic GMP, induced an increase in NAT activity. Light, applied after dark adaptation, inhibited NAT activity. This inhibitory effect was partially prevented in the presence of drugs stimulating cAMP accumulation. In addition, cAMP accumulation and NAT activity increase, induced by forskolin, were temperature dependent. Finally, melatonin release, determined in superfused organs under normal conditions of illumination, was stimulated during the light period of a light/dark cycle by adding an analogue of cAMP or a phosphodiesterase inhibitor. However, no further increase in melatonin release was observed during the dark phase of this cycle in the presence of the drugs. This report shows for the first time that cAMP is a candidate as intracellular second messenger participating in the control of NAT activity and melatonin production by light and temperature.
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Affiliation(s)
- C Thibault
- Laboratoire de Neurobiologie et Neuroendocrinologie Cellularies, URA CNRS 290, Faculté des Sciences, Université de Poitiers, France
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Falcoón J, Bégay V, Besse C, Ravault JP, Collin JP. Pineal photoreceptor cells in culture: fine structure, and light/ dark control of cyclic nucleotide levels and melatonin secretion. J Neuroendocrinol 1992; 4:641-51. [PMID: 21554650 DOI: 10.1111/j.1365-2826.1992.tb00214.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Trout pineal photoreceptor cells were dissociated by trypsin-DNase digestion and further purified by a Percoll gradient centrifugation. Total cells or purified photoreceptor cells were then embedded in a collagen gel, or layered on culture-treated polycarbonate membranes, or maintained in suspension, with RPMI 1640 medium or BGjb medium. It has been shown that cells maintain a rhythmic production of melatonin for at least seven 24 h light/dark cycles under these conditions. In this complementary study, the morphofunctional state of the photoreceptor cells was examined 1) by electron (transmission, scanning) microscopy, and 2) by pharmacological tests under different lighting conditions. Using polycarbonate membranes together with RPMI 1640 medium appeared the most suitable. The segmented organization of photoreceptor cells was well preserved when using the culture-treated membranes. It tended to disappear in cells embedded in the collagen gel and was lost after passage through the Percoll gradient. However, this one allowed obtention of an homogeneous population of photoreceptors, as recognized by their intracellular components. Intracellular organelles were rather well preserved in the embedded photoreceptors. The study also provides novel information on the nature of second messengers involved in the photoperiodic control of melatonin production in photoreceptor cells. From the effects of an adenylyl cyclase activator and a phosphodiesterase inhibitor it appeared that 1) total cells and Percoll-selected cells behaved similarly, 2) the nocturnal rise in melatonin secretion was associated with an increase in cAMP content, and 3) a fall in cAMP may be a mechanism through which light reduces melatonin secretion by photoreceptor cells. Cyclic GMP, the metabolism of which also appeared to be controlled by light, did not seem involved in the photoperiodic control of melatonin production. The method proposed herein offers interesting perspectives for the study of the photoneuroendocrine properties of isolated photoreceptor cells.
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Affiliation(s)
- J Falcoón
- Laboratoire de Neurobiologie et Neuroendocrinologie Cellulaires, URA CNRS 290 et SUMEB, 40 avenue du Recteur Pineau, 86022 Poitiers Cedex, France. INRA, Station de Physiologie de la Reproduction, 37380 Nouzilly, France et Laboratoire de Neuroendocrinologie, Université de Tours, 37200 Tours, France
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