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Was Cajal right about sleep?

Tso MC, Herzog ED - BMC Biol. (2015)

Bottom Line: Cajal's careful observations of the anatomy of the nervous system led him to some lesser-known predictions about the function of glia as mediators of sleep.Reporting over 120 years later in BMC Biology, Bellesi et al. examine changes in gene expression and morphology of astrocytes with sleep.Their results provide support for and revisions to Cajal's predictions.See research article: doi: 10.1186/s12915-015-0176-7 .

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Washington University in St. Louis, St. Louis, MO, 63130, USA.

ABSTRACT
Cajal's careful observations of the anatomy of the nervous system led him to some lesser-known predictions about the function of glia as mediators of sleep. Reporting over 120 years later in BMC Biology, Bellesi et al. examine changes in gene expression and morphology of astrocytes with sleep. Their results provide support for and revisions to Cajal's predictions.See research article: doi: 10.1186/s12915-015-0176-7 .

No MeSH data available.


Related in: MedlinePlus

Historical and current understanding of the role astrocytes in sleep. Top: Cajal postulated that astrocytes retract their processes during wakefulness to allow normal synaptic transmission. During sleep, he reasoned, astrocyte processes invade the synapse to block synaptic transmission. Bottom: Recent findings revise this model to include astrocyte processes covering the synapse, presumably to enhance glutamate clearance during wake and retracting during sleep. This correlates with changes in gene expression in astrocytes (with ~400 transcripts up-regulated during wake and ~50 during sleep) and could relate to more glutamate spillover and increased glymphatic flow during sleep. Previous findings also showed dendritic spines grow with time awake (and greater sleep debt; reviewed in [3]). The model thus posits that changes in glial gene expression, morphology, and physiology may modulate synaptic transmission to promote sleep
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Fig1: Historical and current understanding of the role astrocytes in sleep. Top: Cajal postulated that astrocytes retract their processes during wakefulness to allow normal synaptic transmission. During sleep, he reasoned, astrocyte processes invade the synapse to block synaptic transmission. Bottom: Recent findings revise this model to include astrocyte processes covering the synapse, presumably to enhance glutamate clearance during wake and retracting during sleep. This correlates with changes in gene expression in astrocytes (with ~400 transcripts up-regulated during wake and ~50 during sleep) and could relate to more glutamate spillover and increased glymphatic flow during sleep. Previous findings also showed dendritic spines grow with time awake (and greater sleep debt; reviewed in [3]). The model thus posits that changes in glial gene expression, morphology, and physiology may modulate synaptic transmission to promote sleep

Mentions: The great neuroscientist Santiago Ramón y Cajal (1852–1934) studied neurons extensively and, also, glial cells — astrocytes in particular. Based on his observation that the length of astrocytic processes varies greatly between cells, he imagined that astrocytes dynamically extend and retract their processes. He boldly hypothesized, in 1895, that: (1) during sleep, endfeet of astrocytes invade the synaptic cleft to serve as a ‘circuit breaker’, pausing synaptic transmission and (2) during wakefulness, those endfeet retract, restoring synaptic transmission [1, 2] (Fig. 1).Fig. 1.


Was Cajal right about sleep?

Tso MC, Herzog ED - BMC Biol. (2015)

Historical and current understanding of the role astrocytes in sleep. Top: Cajal postulated that astrocytes retract their processes during wakefulness to allow normal synaptic transmission. During sleep, he reasoned, astrocyte processes invade the synapse to block synaptic transmission. Bottom: Recent findings revise this model to include astrocyte processes covering the synapse, presumably to enhance glutamate clearance during wake and retracting during sleep. This correlates with changes in gene expression in astrocytes (with ~400 transcripts up-regulated during wake and ~50 during sleep) and could relate to more glutamate spillover and increased glymphatic flow during sleep. Previous findings also showed dendritic spines grow with time awake (and greater sleep debt; reviewed in [3]). The model thus posits that changes in glial gene expression, morphology, and physiology may modulate synaptic transmission to promote sleep
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4548903&req=5

Fig1: Historical and current understanding of the role astrocytes in sleep. Top: Cajal postulated that astrocytes retract their processes during wakefulness to allow normal synaptic transmission. During sleep, he reasoned, astrocyte processes invade the synapse to block synaptic transmission. Bottom: Recent findings revise this model to include astrocyte processes covering the synapse, presumably to enhance glutamate clearance during wake and retracting during sleep. This correlates with changes in gene expression in astrocytes (with ~400 transcripts up-regulated during wake and ~50 during sleep) and could relate to more glutamate spillover and increased glymphatic flow during sleep. Previous findings also showed dendritic spines grow with time awake (and greater sleep debt; reviewed in [3]). The model thus posits that changes in glial gene expression, morphology, and physiology may modulate synaptic transmission to promote sleep
Mentions: The great neuroscientist Santiago Ramón y Cajal (1852–1934) studied neurons extensively and, also, glial cells — astrocytes in particular. Based on his observation that the length of astrocytic processes varies greatly between cells, he imagined that astrocytes dynamically extend and retract their processes. He boldly hypothesized, in 1895, that: (1) during sleep, endfeet of astrocytes invade the synaptic cleft to serve as a ‘circuit breaker’, pausing synaptic transmission and (2) during wakefulness, those endfeet retract, restoring synaptic transmission [1, 2] (Fig. 1).Fig. 1.

Bottom Line: Cajal's careful observations of the anatomy of the nervous system led him to some lesser-known predictions about the function of glia as mediators of sleep.Reporting over 120 years later in BMC Biology, Bellesi et al. examine changes in gene expression and morphology of astrocytes with sleep.Their results provide support for and revisions to Cajal's predictions.See research article: doi: 10.1186/s12915-015-0176-7 .

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Washington University in St. Louis, St. Louis, MO, 63130, USA.

ABSTRACT
Cajal's careful observations of the anatomy of the nervous system led him to some lesser-known predictions about the function of glia as mediators of sleep. Reporting over 120 years later in BMC Biology, Bellesi et al. examine changes in gene expression and morphology of astrocytes with sleep. Their results provide support for and revisions to Cajal's predictions.See research article: doi: 10.1186/s12915-015-0176-7 .

No MeSH data available.


Related in: MedlinePlus