Circadian Rhythms in Synaptic Excitability of the Dorsal Lateral Geniculate Nucleus in the Rat

Hanada, Yasuhiro; Kawamura, Hiroshi

doi:10.3109/00207458408990682

Cited by 11 publications

(5 citation statements)

References 20 publications

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“…Hanada and Kawamura reported circadian rhythms in rat visual circuits in vivo that were independent of vigilance state and abolished by SCN lesions [67]. In this study, lateral geniculate nucleus and optic tract responses to stimulation were consistently higher in the dark phase.…”

Section: Circadian Influences On Synaptic Plasticitysupporting

confidence: 61%

Sleep, clocks, and synaptic plasticity

Frank

Cantera

2014

Trends in Neurosciences

107

102

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Sleep is widely believed to play an essential role in synaptic plasticity. However, the precise mechanisms governing this presumptive function are largely unknown. There is also evidence for independent circadian oscillations in synaptic strength and morphology. Therefore, synaptic changes observed after sleep reflect interactions between state-dependent (e.g. wake vs. sleep) and state-independent (circadian) processes. In this article we review how sleep and biological clocks influence synaptic plasticity. We discuss these findings in the context of current plasticity-based theories of sleep function and propose a new model that integrates circadian and brain state influences on synaptic plasticity.

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Section: Circadian Influences On Synaptic Plasticitysupporting

confidence: 61%

Sleep, clocks, and synaptic plasticity

Frank

Cantera

2014

Trends in Neurosciences

107

102

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“…A clear connection between discharge strength, the pattern of thalamic neurons, and the state of arousal has been established 25 , 75 , 76 . Moreover, circadian modulation of visual sensitivity and light-induced responses in the DLG, dependent on the suprachiasmatic nuclei, have been described 32 , 77 . As its best-known function, the orexinergic system is sensitive to arousal and mediates its effects by activating various thalamic and cortical areas.…”

Section: Discussionmentioning

confidence: 99%

Multiple excitatory actions of orexins upon thalamo-cortical neurons in dorsal lateral geniculate nucleus - implications for vision modulation by arousal

Chrobok

Palus-Chramiec

Chrzanowska

et al. 2017

Sci Rep

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The orexinergic system of the lateral hypothalamus plays a crucial role in maintaining wakefulness and mediating arousal in a circadian time-dependent manner. Due to the extensive connections of orexinergic neurons, both orexins (OXA and OXB) exert mainly excitatory effects upon remote brain areas, including the thalamus. The dorsal lateral geniculate nucleus (DLG) is a relay thalamic centre for the visual system. Its thalamo-cortical (TC) neurons convey photic information from the retina to the primary visual cortex. The present study shows that orexins are powerful modulators of neuronal activity in the DLG. OXA directly depolarised the majority of neurons tested, acting predominately on postsynaptic OX2 receptors. Moreover, OXA was found to increase excitability and enhance neuronal responses to both glutamate and γ-aminobutyric acid (GABA). Mechanistic studies showed the involvement of voltage-gated calcium currents and GIRK channels in the observed depolarisations. Immunohistochemical staining showed sparse orexinergic innervation of the DLG during the light phase, with increased density at night. We hypothesise that the depolarising effects of orexins upon DLG neurons may facilitate signal transmission through the visual thalamo-cortical pathway during behavioural arousal. Thus, the action of orexin on DLG TC neurons may underlie the circadian/behavioural modulation of vision.

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“…In addition to these direct effects of melatonin on photoreceptive or retinorecipient structures, photic sensitivity may be modulated indirectly as well. For example, the SCN has been implicated in the regulation of a rhythm of excitability in the dorsal lateral geniculate nucleus (Hanada and Kawamura, 1984). Further, Reuss and Kiefer (1989) have reported that following intravenous injections of melatonin, the spontaneous discharge rate of single cells in the cat striate cortex was reduced and the amplitude of responses to photic stimulation was augmented.…”

Section: Discussionmentioning

confidence: 99%

The Pineal Gland: Photoreception and Coupling of Behavioral, Metabolic, and Cardiovascular Circadian Outputs

Warren

Cassone

1995

J Biol Rhythms

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Although removal of the pineal gland has been shown to have very little effect on the mammalian circadian system in constant darkness (DD), several recent reports have suggested that the mammalian pineal gland may be more important for circadian organization in nocturnal rodents than was previously believed. Removal of the pineal gland (PINX) facilitates the disruptive effects of constant bright light on wheel-running rhythmicity. This suggests at least two possibilities for the role of the pineal gland in the mammalian circadian system. First, pinealectomized rats may perceive ambient light intensity to be brighter than do sham-operated (SHAM) rats. Second, the pineal gland, probably via its secretion of melatonin, may also be involved in coupling components of the circadian system. Coupling, as we see it, may occur at several levels of organization: (1) between retinohypothalamic afferents and suprachiasmatic nuclei (SCN) oscillatory neurons, (2) among multiple SCN oscillators, (3) between the SCN and their multiple outputs, and/or (4) among the multiple circadian outputs themselves. In this study we show that PINX rats free-run with a longer period in four different light intensities than do SHAM rats. Moreover, the rate of increase of tau is greater among PINX rats than among SHAM rats. This supports the first hypothesis. We also show that in PINX rats the circadian rhythms of wheel running, general activity, body temperature, and heart rate are all more disrupted in constant bright light than are those of SHAM rats, and each rhythmic output is disrupted in parallel. This supports the second hypothesis. Melatonin is probably not involved in coupling presynaptic elements of SCN afferents in the retinohypothalamic tract to pacemaking cells within the SCN, since enucleation has no effect on SCN 2-[125I]iodomelatonin (IMEL) binding. Together the data do not discount either of the two hypotheses but do restrict the possible levels at which the pineal gland is involved in coupling. These data also further support a growing body of literature indicating that the pineal gland and its hormone melatonin play a role in mammalian circadian organization.

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Circadian Rhythms in Synaptic Excitability of the Dorsal Lateral Geniculate Nucleus in the Rat

Cited by 11 publications

References 20 publications

Sleep, clocks, and synaptic plasticity

Sleep, clocks, and synaptic plasticity

Multiple excitatory actions of orexins upon thalamo-cortical neurons in dorsal lateral geniculate nucleus - implications for vision modulation by arousal

The Pineal Gland: Photoreception and Coupling of Behavioral, Metabolic, and Cardiovascular Circadian Outputs

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