Fur Seals Display a Strong Drive for Bilateral Slow-Wave Sleep While on Land

Lyamin, Oleg I.; Kosenko, Peter O.; Lapierre, Jennifer L.; Mukhametov, L. M.; Siegel, Jerome M.

doi:10.1523/jneurosci.2306-08.2008

Cited by 31 publications

(41 citation statements)

References 25 publications

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“…In contrast, when a fur seal sleeps in water, its EEG patterns indicate a unihemispheric slow wave (USW) sleep, as in whales and dolphins. 24,259 This switch from BSW sleep on land to USW sleep in water may be an opportunity to address a prediction of the FG hypothesis. In the BSW sleep (on land), when both hemispheres sleep at the same time, specific (e.g., relevant to sleep causation) protein fragments in the two hemispheres of the seal's brain would be expected to be present at equal levels, irrespective of the timing of brain analyses during sleep-wakefulness cycles.…”

Section: Suppression Of Sleep and Unihemispheric Sleepmentioning

confidence: 99%

Augmented generation of protein fragments during wakefulness as the molecular cause of sleep: a hypothesis

Varshavsky

2012

Protein Science

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Despite extensive understanding of sleep regulation, the molecular-level cause and function of sleep are unknown. I suggest that they originate in individual neurons and stem from increased production of protein fragments during wakefulness. These fragments are transient parts of protein complexes in which the fragments were generated. Neuronal Ca 21 fluxes are higher during wakefulness than during sleep. Subunits of transmembrane channels and other proteins are cleaved by Ca 21 -activated calpains and by other nonprocessive proteases, including caspases and secretases. In the proposed concept, termed the fragment generation (FG) hypothesis, sleep is a state during which the production of fragments is decreased (owing to lower Ca 21 transients) while fragment-destroying pathways are upregulated. These changes facilitate the elimination of fragments and the remodeling of protein complexes in which the fragments resided. The FG hypothesis posits that a proteolytic cleavage, which produces two fragments, can have both deleterious effects and fitness-increasing functions. This (previously not considered) dichotomy can explain both the conservation of cleavage sites in proteins and the evolutionary persistence of sleep, because sleep would counteract deleterious aspects of protein fragments. The FG hypothesis leads to new explanations of sleep phenomena, including a longer sleep after sleep deprivation. Studies in the 1970s showed that ethanol-induced sleep in mice can be strikingly prolonged by intracerebroventricular injections of either Ca 21 alone or Ca 21 and its ionophore (Erickson et al., Science 1978;199:1219-1221 Harris, Pharmacol Biochem Behav 1979;10:527-534; Erickson et al., Pharmacol Biochem Behav 1980;12:651-656). These results, which were never interpreted in connection to protein fragments or the function of sleep, may be accounted for by the FG hypothesis about molecular causation of sleep.

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Section: Suppression Of Sleep and Unihemispheric Sleepmentioning

confidence: 99%

Augmented generation of protein fragments during wakefulness as the molecular cause of sleep: a hypothesis

Varshavsky

2012

Protein Science

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“…When the dolphin switches from left to right in the group, the sleep state of the hemispheres changes accordingly [41]. Moreover, seals can exhibit UHSWS as well as bihemispheric slow-wave sleep [42]. Here we stress that, marine mammals have evolved or developed mechanisms for UHSWS but not mechanisms to dispense with sleep altogether.…”

Section: Natural Exceptionsmentioning

confidence: 78%

Is Sleep Beyond Our Control?

Þorsteinsson¹,

Karlsson²

2009

TOSLPJ

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Sleep is mysterious. It is ubiquitous and vital, yet its function remains unknown. There are, however, exceptions from the omnipresence of sleep: Birds that exhibit less sleep drive during migration; cetaceans and dolphins that sidestep the need for sleep by sleeping with one hemisphere at a time; frogs that do not seem to sleep at all; and strains of mice and fruit flies that sleep less than their wild-type counterparts. Moreover, new drugs have been discovered that combat the need for sleep in humans without the well known side effects of common stimulants. In the current review, the different ways of evading sleep will be examined. It will be argued that to understand how sleep can be controlled research efforts need to be extended to non-standard laboratory animals that exhibit different methods of evading sleep. Finally, it is argued that emerging clues point to increased membrane excitability as the common neural process used to execute seemingly different forms of sleep-evasion.

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“…At the same time the frequency and duration of the episodes of SWS with interhemispheric EEG asymmetry increase when compared to baseline conditions [26]. Even under these conditions, the expression of EEG asymmetry in fur seals is generally smaller than in Cetaceans.…”

Section: Comparative Aspects Of Uswsmentioning

confidence: 99%

“…All of the above supports the idea that USWS in marine mammals and birds universally serves to monitor the surroundings via processing of the visual information in the waking hemisphere. At the same time, the waking hemisphere during USWS in marine mammals appears to be capable of processing multimodal information, including auditory [26] and somatosensory (from the vibrissae and moving flipper when sleeping in the lateral position).…”

Section: Usws and Eye Statementioning

confidence: 99%

Sleep in the northern fur seal

Lyamin

Mukhametov

Siegel

2017

Current Opinion in Neurobiology

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The pattern of sleep in the fur seal, a semiaquatic pinniped, has several striking behavioral and physiological adaptations that allow this species to inhabit both the land and water environment. These features include unihemispheric slow wave sleep (USWS, also being unihemispheric waking), the ability to maintain movement for stabilization of the sleep posture and to briefly open one eye while having a sleep electroencephalogram (EEG) in one hemisphere. In vivo microdialysis studies suggest that acetylcholine release is required for cortical activation during USWS, and that monoamines are not required for USWS. The need to breathe, to maintain efficient thermoregulation, and to avoid predation have shaped the sleep patterns in semiaquatic fur seals as in fully aquatic cetaceans.

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Fur Seals Display a Strong Drive for Bilateral Slow-Wave Sleep While on Land

Cited by 31 publications

References 25 publications

Augmented generation of protein fragments during wakefulness as the molecular cause of sleep: a hypothesis

Augmented generation of protein fragments during wakefulness as the molecular cause of sleep: a hypothesis

Is Sleep Beyond Our Control?

Sleep in the northern fur seal

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