1
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Norman H, Munson A, Cortese D, Koeck B, Killen SS. The interplay between sleep and ecophysiology, behaviour and responses to environmental change in fish. J Exp Biol 2024; 227:jeb247138. [PMID: 38860399 DOI: 10.1242/jeb.247138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2024]
Abstract
Evidence of behavioural sleep has been observed in every animal species studied to date, but current knowledge of the behaviour, neurophysiology and ecophysiology associated with sleep is concentrated on mammals and birds. Fish are a hugely diverse group that can offer novel insights into a variety of sleep-related behaviours across environments, but the ecophysiological relevance of sleep in fish has been largely overlooked. Here, we systematically reviewed the literature to assess the current breadth of knowledge on fish sleep, and surveyed the diverse physiological effects and behaviours associated with sleep. We also discuss possible ways in which unstudied external factors may alter sleep behaviours. For example, predation risk may alter sleep patterns, as has been shown in mammalian, avian and reptilian species. Other environmental factors - such as water temperature and oxygen availability - have the potential to alter sleep patterns in fish differently than for terrestrial endotherms. Understanding the ecological influences on sleep in fish is vital, as sleep deprivation has the potential to affect waking behaviour and fitness owing to cognitive and physiological impairments, possibly affecting ecological phenomena and sensitivity to environmental stressors in ways that have not been considered.
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Affiliation(s)
- Helena Norman
- School of Biodiversity, One Health, and Comparative Medicine, University of Glasgow, Glasgow G12 8QQ, UK
| | - Amelia Munson
- School of Biodiversity, One Health, and Comparative Medicine, University of Glasgow, Glasgow G12 8QQ, UK
| | - Daphne Cortese
- School of Biodiversity, One Health, and Comparative Medicine, University of Glasgow, Glasgow G12 8QQ, UK
| | - Barbara Koeck
- School of Biodiversity, One Health, and Comparative Medicine, University of Glasgow, Glasgow G12 8QQ, UK
| | - Shaun S Killen
- School of Biodiversity, One Health, and Comparative Medicine, University of Glasgow, Glasgow G12 8QQ, UK
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2
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Bitsikas V, Cubizolles F, Schier AF. A vertebrate family without a functional Hypocretin/Orexin arousal system. Curr Biol 2024; 34:1532-1540.e4. [PMID: 38490200 DOI: 10.1016/j.cub.2024.02.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 12/20/2023] [Accepted: 02/12/2024] [Indexed: 03/17/2024]
Abstract
The Hypocretin/Orexin signaling pathway suppresses sleep and promotes arousal, whereas the loss of Hypocretin/Orexin results in narcolepsy, including the involuntary loss of muscle tone (cataplexy).1 Here, we show that the South Asian fish species Chromobotia macracanthus exhibits a sleep-like state during which individuals stop swimming and rest on their side. Strikingly, we discovered that the Hypocretin/Orexin system is pseudogenized in C. macracanthus, but in contrast to Hypocretin-deficient mammals, C. macracanthus does not suffer from sudden behavioral arrests. Similarly, zebrafish mutations in hypocretin/orexin show no evident signs of cataplectic-like episodes. Notably, four additional species in the Botiidae family also lack a functional Hypocretin/Orexin system. These findings identify the first vertebrate family that does not rely on a functional Hypocretin/Orexin system for the regulation of sleep and arousal.
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Affiliation(s)
- Vassilis Bitsikas
- Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA; Biozentrum, University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland
| | - Fabien Cubizolles
- Biozentrum, University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland
| | - Alexander F Schier
- Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA; Biozentrum, University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland.
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3
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Singh R, Sharma D, Kumar A, Singh C, Singh A. Understanding zebrafish sleep and wakefulness physiology as an experimental model for biomedical research. FISH PHYSIOLOGY AND BIOCHEMISTRY 2024; 50:827-842. [PMID: 38150068 DOI: 10.1007/s10695-023-01288-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 12/07/2023] [Indexed: 12/28/2023]
Abstract
Sleep is a globally observable fact, or period of reversible distracted rest, that can be distinguished from arousal by various behavioral criteria. Although the function of sleep is an evolutionarily conserved behavior, its mechanism is not yet clear. The zebrafish (Danio rerio) has become a valuable model for neurobehavioral studies such as studying learning, memory, anxiety, and depression. It is characterized by a sleep-like state and circadian rhythm, making it comparable to mammals. Zebrafish are a good model for behavioral studies because they share genetic similarities with humans. A number of neurotransmitters are involved in sleep and wakefulness. There is a binding between melatonin and the hypocretin system present in zebrafish. The full understanding of sleep and wakefulness physiology in zebrafish is still unclear among researchers. Therefore, to make a clear understanding of the sleep/wake cycle in zebrafish, this article covers the mechanism involved behind it, and the role of the neuromodulator system followed by the mechanism of the HPA axis.
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Affiliation(s)
- Rima Singh
- Department of Pharmacology, Delhi Pharmaceutical Sciences & Research University (DPSRU), New Delhi, 110017, India
- Department of Pharmacology, ISF College of Pharmacy, Moga-142001, Affiliated to IK Gujral Punjab Technical University, Jalandhar, Punjab, 144603, India
| | - Deepali Sharma
- Department of Pharmacology, ISF College of Pharmacy, Moga-142001, Affiliated to IK Gujral Punjab Technical University, Jalandhar, Punjab, 144603, India
| | - Anoop Kumar
- Department of Pharmacology, Delhi Pharmaceutical Sciences & Research University (DPSRU), New Delhi, 110017, India
| | - Charan Singh
- Department of Pharmaceutical Sciences, HNB Garhwal University (A Central University), Chauras Campus, Distt, Tehri Garhwal, Uttarakhand, 246174, India
| | - Arti Singh
- Department of Pharmacology, ISF College of Pharmacy, Moga-142001, Affiliated to IK Gujral Punjab Technical University, Jalandhar, Punjab, 144603, India.
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4
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Appleby M, Raoult V, Broadhurst MK, Gaston T. Can denticle morphology help identify southeastern Australian elasmobranchs? JOURNAL OF FISH BIOLOGY 2024. [PMID: 38491854 DOI: 10.1111/jfb.15704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 01/25/2024] [Accepted: 02/13/2024] [Indexed: 03/18/2024]
Abstract
Elasmobranchs are covered in scale-like structures called dermal denticles, comprising dentine and enameloid. These structures vary across the body of an individual and between species, and are frequently shed and preserved in marine sediments. With a good understanding of denticle morphology, current and historical elasmobranch diversity and abundance might be assessed from sediment samples. Here, replicate samples of denticles from the bodies of several known (deceased) shark species were collected and characterized for morphology before being assigned morphotypes. These data were used to expand the established literature describing denticles and to investigate intra- and interspecific variability, with the aim of increasing the viability of using sediment samples to assess elasmobranch diversity and abundance. Denticle morphology was influenced more by life-history traits than by species, where demersal species were largely characterized by generalized function and defense denticles, whereas pelagic and benthopelagic species were characterized by drag-reduction denticles. Almost all species possessed abrasion strength or defense denticles on the snout, precluding their utility for separating species. In a separate manipulative experiment, samples of denticles were collected from sediments in two aquaria with known elasmobranchs to determine their utility for reliably separating species. Visual examination of denticles, morphometric measurements, scaled photographs, and reference collections allowed for some precise identification, but not always to the species level. Ongoing work to develop denticle reference collections could help to identify past and present families and, in some cases, species.
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Affiliation(s)
- Mariah Appleby
- School of Environmental and Life Sciences, University of Newcastle, Ourimbah, New South Wales, Australia
| | - Vincent Raoult
- School of Environmental and Life Sciences, University of Newcastle, Ourimbah, New South Wales, Australia
- Marine Ecology Group, School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Matt K Broadhurst
- NSW Department of Primary Industries, Fisheries Conservation Technology Unit, National Marine Science Centre, Southern Cross University, Coffs Harbour, New South Wales, Australia
- School of the Environment, The University of Queensland, Brisbane, Queensland, Australia
| | - Troy Gaston
- School of Environmental and Life Sciences, University of Newcastle, Ourimbah, New South Wales, Australia
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5
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Bullock RW, Foster C, Lea JSE. Just keep swimming? Observations of resting behavior in gray reef sharks Carcharhinus amblyrhynchos (Bleeker, 1856). JOURNAL OF FISH BIOLOGY 2024; 104:898-900. [PMID: 37983935 DOI: 10.1111/jfb.15623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 11/06/2023] [Accepted: 11/15/2023] [Indexed: 11/22/2023]
Abstract
Understanding the respiratory modes of sharks has important implications for studying the metabolism, energetics, and behavioral strategies of different species. Here we provide the first reported observations of resting behavior in the gray reef shark Carcharhinus amblyrhynchos, a species typically considered an obligate ram ventilator. Observations were made at several locations in the Republic of Seychelles, where sharks were found resting under reef ledges and were unresponsive to the presence of divers. These findings update our understanding of the respiratory mode of this species and have implications for future research.
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Affiliation(s)
- Robert W Bullock
- Save Our Seas Foundation-D'Arros Research Centre, Geneva, Switzerland
| | | | - James S E Lea
- Save Our Seas Foundation, Geneva, Switzerland
- Department of Zoology, University of Cambridge, Cambridge, UK
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6
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Duhart JM, Inami S, Koh K. Many faces of sleep regulation: beyond the time of day and prior wake time. FEBS J 2023; 290:931-950. [PMID: 34908236 PMCID: PMC9198110 DOI: 10.1111/febs.16320] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 12/07/2021] [Accepted: 12/14/2021] [Indexed: 12/19/2022]
Abstract
The two-process model of sleep regulation posits two main processes regulating sleep: the circadian process controlled by the circadian clock and the homeostatic process that depends on the history of sleep and wakefulness. The model has provided a dominant conceptual framework for sleep research since its publication ~ 40 years ago. The time of day and prior wake time are the primary factors affecting the circadian and homeostatic processes, respectively. However, it is critical to consider other factors influencing sleep. Since sleep is incompatible with other behaviors, it is affected by the need for essential behaviors such as eating, foraging, mating, caring for offspring, and avoiding predators. Sleep is also affected by sensory inputs, sickness, increased need for memory consolidation after learning, and other factors. Here, we review multiple factors influencing sleep and discuss recent insights into the mechanisms balancing competing needs.
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Affiliation(s)
- José Manuel Duhart
- Department of Neuroscience, Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia PA
- These authors contributed equally
- Present address: Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Sho Inami
- Department of Neuroscience, Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia PA
- These authors contributed equally
| | - Kyunghee Koh
- Department of Neuroscience, Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia PA
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7
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Rattenborg NC, Ungurean G. The evolution and diversification of sleep. Trends Ecol Evol 2023; 38:156-170. [PMID: 36411158 DOI: 10.1016/j.tree.2022.10.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 10/17/2022] [Accepted: 10/24/2022] [Indexed: 11/19/2022]
Abstract
The evolutionary origins of sleep and its sub-states, rapid eye movement (REM) and non-REM (NREM) sleep, found in mammals and birds, remain a mystery. Although the discovery of a single type of sleep in jellyfish suggests that sleep evolved much earlier than previously thought, it is unclear when and why sleep diversified into multiple types of sleep. Intriguingly, multiple types of sleep have recently been found in animals ranging from non-avian reptiles to arthropods to cephalopods. Although there are similarities between these states and those found in mammals and birds, notable differences also exist. The diversity in the way sleep is expressed confounds attempts to trace the evolution of sleep states, but also serves as a rich resource for exploring the functions of sleep.
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Affiliation(s)
- Niels C Rattenborg
- Max Planck Institute for Biological Intelligence (in foundation), Seewiesen, Germany.
| | - Gianina Ungurean
- Max Planck Institute for Biological Intelligence (in foundation), Seewiesen, Germany
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8
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Wheeler CR, Kneebone J, Heinrich D, Strugnell JM, Mandelman JW, Rummer JL. Diel Rhythm and Thermal Independence of Metabolic Rate in a Benthic Shark. J Biol Rhythms 2022; 37:484-497. [PMID: 35822624 DOI: 10.1177/07487304221107843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Biological rhythms that are mediated by exogenous factors, such as light and temperature, drive the physiology of organisms and affect processes ranging from cellular to population levels. For elasmobranchs (i.e. sharks, rays, and skates), studies documenting diel activity and movement patterns indicate that many species are crepuscular or nocturnal in nature. However, few studies have investigated the rhythmicity of elasmobranch physiology to understand the mechanisms underpinning these distinct patterns. Here, we assess diel patterns of metabolic rates in a small meso-predator, the epaulette shark (Hemiscyllium ocellatum), across ecologically relevant temperatures and upon acutely removing photoperiod cues. This species possibly demonstrates behavioral sleep during daytime hours, which is supported herein by low metabolic rates during the day and a 1.7-fold increase in metabolic rates at night. From spring to summer seasons, where average average water temperature temperatures for this species range 24.5 to 28.5 °C, time of day, and not temperature, had the strongest influence on metabolic rate. These results indicate that this species, and perhaps other similar species from tropical and coastal environments, may have physiological mechanisms in place to maintain metabolic rate on a seasonal time scale regardless of temperature fluctuations that are relevant to their native habitats.
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Affiliation(s)
- Carolyn R Wheeler
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland, Australia.,School for the Environment, The University of Massachusetts Boston, Boston, Massachusetts
| | - Jeff Kneebone
- Anderson Cabot Center for Ocean Life, New England Aquarium, Boston, Massachusetts
| | - Dennis Heinrich
- College of Science and Engineering, Flinders University, Adelaide, South Australia, Australia
| | - Jan M Strugnell
- Centre for Sustainable Tropical Fisheries and Aquaculture, James Cook University, Townsville, Queensland, Australia.,Department of Ecology, Environment and Evolution, La Trobe University, Melbourne, Victoria, Australia
| | - John W Mandelman
- School for the Environment, The University of Massachusetts Boston, Boston, Massachusetts.,Anderson Cabot Center for Ocean Life, New England Aquarium, Boston, Massachusetts
| | - Jodie L Rummer
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland, Australia.,College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
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9
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Kelly ML, Collins SP, Lesku JA, Hemmi JM, Collin SP, Radford CA. Energy conservation characterizes sleep in sharks. Biol Lett 2022; 18:20210259. [PMID: 35259943 PMCID: PMC8915397 DOI: 10.1098/rsbl.2021.0259] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Sharks represent the earliest group of jawed vertebrates and as such, they may provide original insight for understanding the evolution of sleep in more derived animals. Unfortunately, beyond a single behavioural investigation, very little is known about sleep in these ancient predators. As such, recordings of physiological indicators of sleep in sharks have never been reported. Reduced energy expenditure arising from sustained restfulness and lowered metabolic rate during sleep have given rise to the hypothesis that sleep plays an important role for energy conservation. To determine whether this idea applies also to sharks, we compared metabolic rates of draughtsboard sharks (Cephaloscyllium isabellum) during periods ostensibly thought to be sleep, along with restful and actively swimming sharks across a 24 h period. We also investigated behaviours that often characterize sleep in other animals, including eye closure and postural recumbency, to establish relationships between physiology and behaviour. Overall, lower metabolic rate and a flat body posture reflect sleep in draughtsboard sharks, whereas eye closure is a poorer indication of sleep. Our results support the idea for the conservation of energy as a function of sleep in these basal vertebrates.
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Affiliation(s)
- Michael L Kelly
- School of Life Sciences, La Trobe University, Melbourne, Australia
| | - Selwyn P Collins
- Institute of Marine Science, Leigh Marine Laboratory, The University of Auckland, Auckland, New Zealand
| | - John A Lesku
- School of Life Sciences, La Trobe University, Melbourne, Australia
| | - Jan M Hemmi
- School of Biological Sciences, The University of Western Australia, Perth, Australia.,Oceans Institute, The University of Western Australia, Perth, Australia
| | - Shaun P Collin
- School of Life Sciences, La Trobe University, Melbourne, Australia.,Oceans Institute, The University of Western Australia, Perth, Australia.,Oceans Graduate School, The University of Western Australia, Perth, Australia
| | - Craig A Radford
- Institute of Marine Science, Leigh Marine Laboratory, The University of Auckland, Auckland, New Zealand
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10
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Pandey A, Oliver R, Kar SK. Differential Gene Expression in Brain and Liver Tissue of Wistar Rats after Rapid Eye Movement Sleep Deprivation. Clocks Sleep 2020; 2:442-465. [PMID: 33114225 PMCID: PMC7711450 DOI: 10.3390/clockssleep2040033] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/13/2020] [Accepted: 10/21/2020] [Indexed: 02/06/2023] Open
Abstract
Sleep is essential for the survival of most living beings. Numerous researchers have identified a series of genes that are thought to regulate "sleep-state" or the "deprived state". As sleep has a significant effect on physiology, we believe that lack of total sleep, or particularly rapid eye movement (REM) sleep, for a prolonged period would have a profound impact on various body tissues. Therefore, using the microarray method, we sought to determine which genes and processes are affected in the brain and liver of rats following nine days of REM sleep deprivation. Our findings showed that REM sleep deprivation affected a total of 652 genes in the brain and 426 genes in the liver. Only 23 genes were affected commonly, 10 oppositely, and 13 similarly across brain and liver tissue. Our results suggest that nine-day REM sleep deprivation differentially affects genes and processes in the brain and liver of rats.
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Affiliation(s)
- Atul Pandey
- School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
- Department of Ecology, Evolution, and Behavior, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel;
| | - Ryan Oliver
- Department of Ecology, Evolution, and Behavior, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel;
| | - Santosh K Kar
- School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
- Nano Herb Research Laboratory, Kalinga Institute of Industrial Technology (KIIT) Technology Bio Incubator, Campus-11, KIIT Deemed to be University, Bhubaneswar, Odisha 751024, India
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11
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Comparative Perspectives that Challenge Brain Warming as the Primary Function of REM Sleep. iScience 2020; 23:101696. [PMID: 33196022 PMCID: PMC7644584 DOI: 10.1016/j.isci.2020.101696] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 09/17/2020] [Accepted: 10/14/2020] [Indexed: 01/04/2023] Open
Abstract
Rapid eye movement (REM) sleep is a paradoxical state of wake-like brain activity occurring after non-REM (NREM) sleep in mammals and birds. In mammals, brain cooling during NREM sleep is followed by warming during REM sleep, potentially preparing the brain to perform adaptively upon awakening. If brain warming is the primary function of REM sleep, then it should occur in other animals with similar states. We measured cortical temperature in pigeons and bearded dragons, lizards that exhibit NREM-like sleep and REM-like sleep with brain activity resembling wakefulness. In pigeons, cortical temperature decreased during NREM sleep and increased during REM sleep. However, brain temperature did not increase when dragons switched from NREM-like to REM-like sleep. Our findings indicate that brain warming is not a universal outcome of sleep states characterized by wake-like activity, challenging the hypothesis that their primary function is to warm the brain in preparation for wakefulness. In many mammals, the brain cools during non-REM sleep and warms during REM sleep Pigeons exhibit similar changes in cortical temperature during non-REM and REM sleep Brain temperature does not increase during REM-like sleep in bearded dragon lizards Brain warming is not a universal outcome of sleep states with wake-like brain activity
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12
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Kelly ML, Spreitzenbarth S, Kerr CC, Hemmi JM, Lesku JA, Radford CA, Collin SP. Behavioural sleep in two species of buccal pumping sharks (Heterodontus portusjacksoni and Cephaloscyllium isabellum). J Sleep Res 2020; 30:e13139. [PMID: 32672393 DOI: 10.1111/jsr.13139] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 06/23/2020] [Accepted: 06/23/2020] [Indexed: 11/28/2022]
Abstract
Sleep is known to occur in most, if not all, animals studied thus far. Recent studies demonstrate the presence of sleep in flatworms and jellyfish, suggesting that this behaviour evolved early in the evolution of animals. Sharks are the earliest known extant, jawed vertebrates and may play an important role in understanding the evolutionary history of sleep in vertebrates, and yet, it is unknown whether they sleep. The Port Jackson (Heterodontus portusjacksoni) and draughtsboard (Cephaloscyllium isabellum) sharks are both benthic, buccal pumping species and remain motionless for extended periods of time. Whether these periods of prolonged inactivity represent sleep or quiet wakefulness is unknown. A key criterion for separating sleep from other quiescent states is an increased arousal threshold. We show here that inactive sharks of both species require significantly higher levels of electric stimulation before they show a visible response. Sharks deprived of rest, however, show no significant compensatory increase in restfulness during their normal active period following enforced swimming. Nonetheless, increased arousal thresholds in inactive animals suggest that these two species of shark sleep - the first such demonstration for members of this group of vertebrates. Further research, including electrophysiological studies, on these and other sharks, is required for a comprehensive understanding of sleep in cartilaginous fishes.
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Affiliation(s)
- Michael L Kelly
- School of Biological Sciences, The University of Western Australia, Perth, Australia.,Oceans Institute, The University of Western Australia, Perth, Australia.,Oceans Graduate School, The University of Western Australia, Perth, Australia
| | - Stefan Spreitzenbarth
- Leigh Marine Laboratory, Institute of Marine Science, The University of Auckland, Auckland, New Zealand
| | - Caroline C Kerr
- School of Life Sciences, La Trobe University, Melbourne, Australia
| | - Jan M Hemmi
- School of Biological Sciences, The University of Western Australia, Perth, Australia.,Oceans Institute, The University of Western Australia, Perth, Australia
| | - John A Lesku
- School of Life Sciences, La Trobe University, Melbourne, Australia
| | - Craig A Radford
- Leigh Marine Laboratory, Institute of Marine Science, The University of Auckland, Auckland, New Zealand
| | - Shaun P Collin
- Oceans Institute, The University of Western Australia, Perth, Australia.,Oceans Graduate School, The University of Western Australia, Perth, Australia.,School of Life Sciences, La Trobe University, Melbourne, Australia
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13
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Kelly ML, Murray ERP, Kerr CC, Radford CA, Collin SP, Lesku JA, Hemmi JM. Diverse Activity Rhythms in Sharks (Elasmobranchii). J Biol Rhythms 2020; 35:476-488. [PMID: 32525441 DOI: 10.1177/0748730420932066] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Sharks are an interesting group of vertebrates, as many species swim continuously to "ram" oxygen-rich seawater over their gills (ram ventilators), whereas other species "pump" seawater over their gills by manipulating buccal cavity volume while remaining motionless (buccal pumpers). This difference in respiratory physiology raises the question: What are the implications of these differences in lifestyle for circadian rhythms? We investigated the diel activity patterns of 5 species of sharks, including 3 ram ventilating species: the school shark (Galeorhinus galeus), the spotted estuary smooth-hound (Mustelus lenticulatus), and the spiny dogfish (Squalus acanthias); and 2 buccal pumping species: the Port Jackson (Heterodontus portusjacksoni) and draughtsboard (Cephaloscyllium isabellum) sharks. We measured the amount, duration, and distance traveled while swimming over multiple days under a 12:12 light:dark light regime for all species and used modified light regimes for species with a clear diel rhythm in activity. We identified a surprising diversity of activity rhythms. The school shark and smooth-hound swam continuously; however, whereas the school shark swam at the same speed and covered the same distance during the day and night, the smooth-hound swam slower at night and traversed a shorter distance. A similar pattern was observed in the spiny dogfish, although this shark swam less overall. Both the Port Jackson and draughtsboard sharks showed a marked nocturnal preference for swimming. This pattern was muted and disrupted during constant light and constant dark regimes, although circadian organization of this pattern was maintained under certain conditions. The consequences of these patterns for other biological processes, such as sleep, remain unclear. Nonetheless, these 5 species demonstrate remarkable diversity within the activity rhythms of sharks.
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Affiliation(s)
- Michael L Kelly
- School of Biological Sciences, The University of Western Australia, Perth, Australia.,Oceans Institute, The University of Western Australia, Perth, Australia.,Oceans Graduate School, The University of Western Australia, Perth, Australia
| | - Errol R P Murray
- Institute of Marine Science, Leigh Marine Laboratory, The University of Auckland, Auckland, New Zealand
| | - Caroline C Kerr
- School of Life Sciences, La Trobe University, Melbourne, Australia
| | - Craig A Radford
- Institute of Marine Science, Leigh Marine Laboratory, The University of Auckland, Auckland, New Zealand
| | - Shaun P Collin
- Oceans Institute, The University of Western Australia, Perth, Australia.,Oceans Graduate School, The University of Western Australia, Perth, Australia.,School of Life Sciences, La Trobe University, Melbourne, Australia
| | - John A Lesku
- School of Life Sciences, La Trobe University, Melbourne, Australia
| | - Jan M Hemmi
- School of Biological Sciences, The University of Western Australia, Perth, Australia.,Oceans Institute, The University of Western Australia, Perth, Australia
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14
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Ungurean G, van der Meij J, Rattenborg NC, Lesku JA. Evolution and plasticity of sleep. CURRENT OPINION IN PHYSIOLOGY 2020. [DOI: 10.1016/j.cophys.2019.12.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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