Correspondence

Nagao, S; Kwak, Shin; Kanazawa, Ichiro

doi:10.1016/s0306-4522(97)00021-3

Cited by 66 publications

(18 citation statements)

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“…In particular, excitatory amino acid transporters (EAATs) act to limit EPSCs at parallel fiber synapses onto PCs [29]–[31]. One of these transporters, EAAT4, is found predominantly at perisynaptic regions on the PC dendritic membrane, and is highly expressed in Z+ PCs but not Z− PCs [25], [26], [67]. Given this differential expression of EAAT4, the excitatory drive from parallel fibers could be weaker in Z+ PCs, thereby leading to lower SS rates.…”

Section: Discussionmentioning

confidence: 99%

“…Moreover, the expression patterns of a number of other genes can be straightforwardly mapped onto that of zebrin, and many of these likely affect neuronal activity. For example, excitatory amino acid transporter 4 (EAAT4), which is preferentially localized to perisynaptic regions of the PC dendritic plasma membrane, is much more highly expressed in Z+ than Z− PCs [25], [26], and loss of its activity significantly enhances both parallel fiber and climbing fiber evoked EPSCs [27]–[32].…”

Section: Introductionmentioning

confidence: 99%

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Systematic Regional Variations in Purkinje Cell Spiking Patterns

et al. 2014

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In contrast to the uniform anatomy of the cerebellar cortex, molecular and physiological studies indicate that significant differences exist between cortical regions, suggesting that the spiking activity of Purkinje cells (PCs) in different regions could also show distinct characteristics. To investigate this possibility we obtained extracellular recordings from PCs in different zebrin bands in crus IIa and vermis lobules VIII and IX in anesthetized rats in order to compare PC firing characteristics between zebrin positive (Z+) and negative (Z−) bands. In addition, we analyzed recordings from PCs in the A2 and C1 zones of several lobules in the posterior lobe, which largely contain Z+ and Z− PCs, respectively. In both datasets significant differences in simple spike (SS) activity were observed between cortical regions. Specifically, Z− and C1 PCs had higher SS firing rates than Z+ and A2 PCs, respectively. The irregularity of SS firing (as assessed by measures of interspike interval distribution) was greater in Z+ bands in both absolute and relative terms. The results regarding systematic variations in complex spike (CS) activity were less consistent, suggesting that while real differences can exist, they may be sensitive to other factors than the cortical location of the PC. However, differences in the interactions between SSs and CSs, including the post-CS pause in SSs and post-pause modulation of SSs, were also consistently observed between bands. Similar, though less strong trends were observed in the zonal recordings. These systematic variations in spontaneous firing characteristics of PCs between zebrin bands in vivo, raises the possibility that fundamental differences in information encoding exist between cerebellar cortical regions.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Systematic Regional Variations in Purkinje Cell Spiking Patterns

et al. 2014

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“…Among the best characterized of the proteins that co-localize with zebrin II is EAAT4 46, 89–91 . EAAT4 is expressed exclusively by Purkinje cells and acts to limit the duration of action of glutamate at climbing fibre and parallel fibre synapses, and also to limit its diffusion to extrasynaptic receptors and to receptors in nearby synapses 92–96 .…”

Section: Patterned Physiologymentioning

confidence: 99%

Redefining the cerebellar cortex as an assembly of non-uniform Purkinje cell microcircuits

et al. 2015

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The adult mammalian cerebellar cortex is generally assumed to have a uniform cytoarchitecture. Differences in cerebellar function are thought to arise, in the main, through distinct patterns of input and output connectivity, rather than as a result of variations in cortical microcircuitry. However, evidence from anatomical, physiological and genetic studies is increasingly challenging this orthodoxy and there are now various lines of evidence that the cerebellar cortex is non uniform. Here we develop the hypothesis that regional differences in cerebellar cortical microcircuit properties lead to important differences in information processing.

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“…EAAT4 expression is enriched in Purkinje cells of the cerebellum, but is also found at lower levels in other cells in the brain (Dehnes et al, 1998; Furuta et al, 1997; Massie et al, 2001; Massie et al, 2008; Nagao et al, 1997; Tanaka et al, 1997a). EAAT5 is found on the presynaptic termini of retinal bipolar cells (Pow and Barnett, 2000; Schneider et al, 2014; Wersinger et al, 2006).…”

Section: Introduction To Glutamate Transportersmentioning

confidence: 99%

Astroglial glutamate transporters coordinate excitatory signaling and brain energetics

Robinson

Jackson

2016

Neurochemistry International

137

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In the mammalian brain, a family of sodium-dependent transporters maintains low extracellular glutamate and shapes excitatory signaling. The bulk of this activity is mediated by the astroglial glutamate transporters GLT-1 and GLAST (also called EAAT2 and EAAT1). In this review, we will discuss evidence that these transporters co-localize with, form physical (co-immunoprecipitable) interactions with, and functionally couple to various ‘energy-generating’ systems, including the Na+/K+-ATPase, the Na+/Ca2+ exchanger, glycogen metabolizing enzymes, glycolytic enzymes, and mitochondria/mitochondrial proteins. This functional coupling is bidirectional with many of these systems both being regulated by glutamate transport and providing the ‘fuel’ to support glutamate uptake. Given the importance of glutamate uptake to maintaining synaptic signaling and preventing excitotoxicity, it should not be surprising that some of these systems appear to ‘redundantly’ support the energetic costs of glutamate uptake. Although the glutamate-glutamine cycle contributes to recycling of neurotransmitter pools of glutamate, this is an over-simplification. The ramifications of co-compartmentalization of glutamate transporters with mitochondria for glutamate metabolism are discussed. Energy consumption in the brain accounts for ~20% of the basal metabolic rate and relies almost exclusively on glucose for the production of ATP. However, the brain does not possess substantial reserves of glucose or other fuels. To ensure adequate energetic supply, increases in neuronal activity are matched by increases in cerebral blood flow via a process known as ‘neurovascular coupling’. While the mechanisms for this coupling are not completely resolved, it is generally agreed that astrocytes, with processes that extend to synapses and endfeet that surround blood vessels, mediate at least some of the signal that causes vasodilation. Several studies have shown that either genetic deletion or pharmacologic inhibition of glutamate transport impairs neurovascular coupling. Together these studies strongly suggest that glutamate transport not only coordinates excitatory signaling, but also plays a pivotal role in regulating brain energetics.

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Correspondence

Cited by 66 publications

References 0 publications

Systematic Regional Variations in Purkinje Cell Spiking Patterns

Systematic Regional Variations in Purkinje Cell Spiking Patterns

Redefining the cerebellar cortex as an assembly of non-uniform Purkinje cell microcircuits

Astroglial glutamate transporters coordinate excitatory signaling and brain energetics

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