The pineal organ of teleost fishes
01 Jun 1997-Reviews in Fish Biology and Fisheries (Kluwer Academic Publishers)-Vol. 7, Iss: 2, pp 199-284
TL;DR: There are strong indications that the pineal organ is one component in a central neural system that constitutes the photoperiod-responding system of the animal, i.e. the system that is responsible for correct timing of daily and seasonal physiological rhythms.
Abstract: The pineal organ of teleost fish is a directly photosensory organ that contains photoreceptor cells similar to those of the retina. It conveys photoperiod information to the brain via neural pathways and by release of indoleamines, primarily melatonin, into the circulation. The photoreceptor cells respond to changes in ambient illumination with a gradual modulation of neurotransmission to second-order neurons that innervate various brain centres, and by modulation of indoleamine synthesis. Melatonin is produced rhythmically, and melatonin synthesis may be regulated either directly by ambient photoperiod, or by an endogenous circadian oscillator that is entrained by the photoperiod. During natural conditions, melatonin is produced at highest levels during the night. Although the pineal organ undoubtedly influences a variety of physiological parameters, as assessed by experimental removal of the pineal organ and/or administration of exogenous indoleamines, its role in any physiological situation is not clear cut. The effects of any interference with pineal functions appear to vary with the time of year and experimental photothermal regimes. There are strong indications that the pineal organ is one component in a central neural system that constitutes the photoperiod-responding system of the animal, i.e. the system that is responsible for correct timing of daily and seasonal physiological rhythms. It is important to envisage the pineal organ as a part of this system; it interacts with other photosensory structures (the retina, possibly extraretinal non-pineal photoreceptors) and circadian rhythm generators
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724 citations
TL;DR: How manipulation of the photic cues impact on fish circannual clock and annual cycle of reproduction, and how this can be used for aquaculture purposes is discussed.
386 citations
TL;DR: This review focuses on the functional properties of the cellular circadian clocks of non-mammalian vertebrates and how functions the clock?
295 citations
TL;DR: The epithalamus is a major subdivision of the diencephalon constituted by the habenular nuclei and pineal complex and Connectivity of the parapineal organ with the left habenula is not always coupled with asymmetries in ha benular size and/or neuronal organisation suggesting that, at least in some species, assignment of parapineAL and habenul asymmetry may be independent events.
Abstract: The epithalamus is a major subdivision of the diencephalon constituted by the habenular nuclei and pineal complex. Structural asymmetries in this region are widespread amongst vertebrates and involve differences in size, neuronal organisation, neurochemistry and connectivity. In species that possess a photoreceptive parapineal organ, this structure projects asymmetrically to the left habenula, and in teleosts it is also situated on the left side of the brain. Asymmetries in size between the left and right sides of the habenula are often associated with asymmetries in neuronal organisation, although these two types of asymmetry follow different evolutionary courses. While the former is more conspicuous in fishes (with the exception of teleosts), asymmetries in neuronal organisation are more robust in amphibia and reptiles. Connectivity of the parapineal organ with the left habenula is not always coupled with asymmetries in habenular size and/or neuronal organisation suggesting that, at least in some species, assignment of parapineal and habenular asymmetries may be independent events.The evolutionary origins of epithalamic structures are uncertain but asymmetry in this region is likely to have existed at the origin of the vertebrate, perhaps even the chordate, lineage. In at least some extant vertebrate species, epithalamic asymmetries are established early in development, suggesting a genetic regulation of asymmetry. In some cases, epigenetic factors such as hormones also influence the development of sexually dimorphic habenular asymmetries. Although the genetic and developmental mechanisms by which neuroanatomical asymmetries are established remain obscure, some clues regarding the mechanisms underlying laterality decisions have recently come from studies in zebrafish. The Nodal signalling pathway regulates laterality by biasing an otherwise stochastic laterality decision to the left side of the epithalamus. This genetic mechanism ensures a consistency of epithalamic laterality within the population. Between species, the laterality of asymmetry is variable and a clear evolutionary picture is missing. We propose that epithalamic structural asymmetries per se and not the laterality of these asymmetries are important for the behaviour of individuals within a species. A consistency of the laterality within a population may play a role in social behaviours between individuals of the species.
257 citations
TL;DR: This review aims to bring together the current knowledge on the photic control of reproduction mainly focusing on seasonal temperate fish species and shape the current working hypotheses supported by recent findings obtained in teleosts or based on knowledge gathered in mammalian and avian species.
Abstract: Seasonality is an important adaptive trait in temperate fish species as it entrains or regulates most physiological events such as reproductive cycle, growth profile, locomotor activity and key life-stage transitions. Photoperiod is undoubtedly one of the most predictable environmental signals that can be used by most living organisms including fishes in temperate areas. This said, however, understanding of how such a simple signal can dictate the time of gonadal recruitment and spawning, for example, is a complex task. Over the past few decades, many scientists attempted to unravel the roots of photoperiodic signalling in teleosts by investigating the role of melatonin in reproduction, but without great success. In fact, the hormone melatonin is recognized as the biological time-keeping hormone in fishes mainly due to the fact that it reflects the seasonal variation in daylength across the whole animal kingdom rather than the existence of direct evidences of its role in the entrainment of reproduction in fishes. Recently, however, some new studies clearly suggested that melatonin interacts with the reproductive cascade at a number of key steps such as through the dopaminergic system in the brain or the synchronization of the final oocyte maturation in the gonad. Interestingly, in the past few years, additional pathways have become apparent in the search for a fish photoneuroendocrine system including the clock-gene network and kisspeptin signalling and although research on these topics are still in their infancy, it is moving at great pace. This review thus aims to bring together the current knowledge on the photic control of reproduction mainly focusing on seasonal temperate fish species and shape the current working hypotheses supported by recent findings obtained in teleosts or based on knowledge gathered in mammalian and avian species. Four of the main potential regulatory systems (light perception, melatonin, clock genes and kisspeptin) in fish reproduction are reviewed.
248 citations
References
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27 Feb 2006
TL;DR: In this paper, the authors present a hierarchy of classes of the classes of Acanthodysseus: Superorder Ateleopodomorpha, Superorder Protacanthopterygii.
Abstract: PREFACE. ACKNOWLEDGMENTS. INTRODUCTION. PHYLUM CHORDATA. Subphylum Craniata. Superclass Myxinomorphi to Osteostracomorphi. Superclass Gnathostomata. +Class Placodermi. Class Chondrichthyes. Subclass Holocephali. Order Chimaeriformes. Subclass Elasmobranchii. Order Heterodontiformes. Order Orectolobiformes. Order Lamniformes. Order Carcharhiniformes. Order Hexanchiformes. Order Echinorhiniformes. Order Squaliformes. Order Squatiniformes. Order Pristiophoriformes. Order Torpediniformes. Order Pristiformes. Order Rajiformes. Order Myliobatiformes. +Class Acanthodii. Class Actinopterygii. Subclass Cladistia. Order Polypteriformes. Subclass Chrondrostei. Order Acipenseriformes. Subclass Neopterygii. Order Lepisosteiformes. Order Amiiformes. Division Teleostei. Subdivision Osteoglossomorpha. Order Hiodontiformes. Order Osteoglossiformes. Subdivision Elopomorpha. Order Elopiformes. Order Albuliformes. Order Anguilliformes. Order Saccopharyngiformes. Subdivision Ostarioclupeomorpha (= Otocephala). Superorder Clupeomorpha. Order Clupeiformes. Superorder Ostariophysi. Order Gonorynchiformes. Order Cypriniformes. Order Characiformes. Order Siluriformes. Order Gymnotiformes. Subdivision Euteleostei. Superorder Protacanthopterygii. Order Argentiniformes. Order Osmeriformes. Order Salmoniformes. Order Esociformes. Superorder Stenopterygii. Order Stomiiformes. Superorder Ateleopodomorpha. Order Ateleopodiformes. Superorder Cyclosquamata. Order Aulopiformes. Superorder Scopelomorpha. Order Myctophiformes. Superorder Lampriomorpha. Order Lampriformes. Superorder Polymixiomorpha. Order Polymixiiformes. Superorder Paracanthopterygii. Order Percopsiformes. Order Gadiformes. Order Ophidiiformes. Order Batrachoidiformes. Order Lophiiformes. Superorder Acanthopterygii. Series Mugilomorpha. Order Mugiliformes. Series Atherinomorpha. Order Atheriniformes. Order Beloniformes. Order Cyprinodontiformes. Series Percomorpha. Order Stephanoberyciformes. Order Beryciformes. Order Zeiformes. Order Gasterosteiformes. Order Synbranchiformes. Order Scorpaeniformes. Order Perciformes. Order Pleuronectiformes. Order Tetraodontiformes. Class Sarcopterygii. Subclass Coelacanthimorpha. Order Coelacanthiformes. Subclass Dipnotetrapodomorpha. Order Ceratodontiformes. Unranked Tetrapodomorpha. Infraclass Tetrapoda. APPENDIX. BIBLIOGRAPHY. INDEX.
5,681 citations
TL;DR: This chapter discusses the gamma-aminobutyric acid (GABA) receptor channels, which are the most abundant inhibitory neurotransmitter in the CNS.
Abstract: This chapter discusses the gamma-aminobutyric acid (GABA) receptor channels, which are the most abundant inhibitory neurotransmitter in the CNS. Following release from presynaptic vesicles, GABA exerts fast inhibitory effects by interacting with GABA receptors, whose primary function is to hyperpolarize neuronal membranes in mature CNS neurons. GABA receptors are found both presynaptically, where they decrease the likelihood of neurotransmitter release, and postsynaptically, where they decrease the likelihood of neuronal firing. There are two types of GABA receptor, termed GABA A and GABA B receptors. GABA A receptors are fast-activating Clˉ channels from the Cys-loop family of ligand-gated ion channels. Activation of GABA A receptors causes membrane hyperpolarization by allowing Clˉ influx, reflecting the relatively low concentration of Clˉ found intracellularly in most adult CNS neurons. GABA A receptors can also mediate depolarizing responses in most immature CNS neurons and in mature peripheral neurons.
1,991 citations
"The pineal organ of teleost fishes" refers background in this paper
...As benzodiazepines are known to potentiate the action of GABA at the GABAA=benzodiazepine receptor complex (Macdonald and Olsen, 1994), the pronounced influence of benzodiazepines but lack of effect of GABAA ligands needs further exploration....
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TL;DR: In this article, Axelrod applied signal transduction theory to his research on the metabolic function of serotonin, even describing the pineal gland as a "neurochemical transducer."
Abstract: In this article, Axelrod applied signal transduction theory to his research on the metabolic function of serotonin, even describing
the pineal gland as a "neurochemical transducer."
847 citations
"The pineal organ of teleost fishes" refers background in this paper
...1) and not much later it was demonstrated that melatonin synthesis is indirectly controlled by the daily dark–light cycle (Axelrod, 1974)....
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TL;DR: The results implicate CREB in neuronal signaling in the hypothalamus and suggest that circadian clock gating of light-regulated molecular responses in the SCN occurs upstream of phosphorylation of CREB.
Abstract: Mammalian circadian rhythms are regulated by a pacemaker within the suprachiasmatic nuclei (SCN) of the hypothalamus. The molecular mechanisms controlling the synchronization of the circadian pacemaker are unknown; however, immediate early gene (IEG) expression in the SCN is tightly correlated with entrainment of SCN-regulated rhythms. Antibodies were isolated that recognize the activated, phosphorylated form of the transcription factor cyclic adenosine monophosphate response element binding protein (CREB). Within minutes after exposure of hamsters to light, CREB in the SCN became phosphorylated on the transcriptional regulatory site, Ser133. CREB phosphorylation was dependent on circadian time: CREB became phosphorylated only at times during the circadian cycle when light induced IEG expression and caused phase shifts of circadian rhythms. These results implicate CREB in neuronal signaling in the hypothalamus and suggest that circadian clock gating of light-regulated molecular responses in the SCN occurs upstream of phosphorylation of CREB.
818 citations
"The pineal organ of teleost fishes" refers background in this paper
...one may speculate that they activate a Ca=cAMP response element (CaCRE) in a mode similar to that by which the c-fos gene is activated by phase-shift-inducing light stimuli in the suprachiasmatic nucleus of rodents (Ginty et al., 1993; Takahashi et al., 1993; Takeuchi et al., 1993)....
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...…in darkness, one may speculate that they activate a Ca=cAMP response element (CaCRE) in a mode similar to that by which the c-fos gene is activated by phase-shift-inducing light stimuli in the suprachiasmatic nucleus of rodents (Ginty et al., 1993; Takahashi et al., 1993; Takeuchi et al., 1993)....
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