Spermine/spermidine is expressed by retinal glial (müller) cells and controls distinct K
            <sup>+</sup>
            channels of their membrane

Biedermann, Bernd; Skatchkov, Serguei N.; Brunk, Irene; Bringmann, Andreas; Pannicke, Thomas; Bernstein, Hans‐Gert; Faude, Frank; Germer, Angela; Veh, Rüdiger W.; Reichenbach, Andreas

doi:10.1002/(sici)1098-1136(199807)23:3<209::aid-glia4>3.0.co;2-#

Cited by 66 publications

(63 citation statements)

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“…ATP (3 mM) was used in the ICS to inhibit Kir 6.1/SUR1 (K(ATP)) channels [45]. Spermine (250 µM) was added to the ICS to block the outward component of Kir channels [67], [68]. Addition of spermine in the ICS also helped to separate TASK-mediated currents from Kir currents [47].…”

Section: Methodsmentioning

confidence: 99%

Unidirectional Photoreceptor-to-Müller Glia Coupling and Unique K+ Channel Expression in Caiman Retina

et al. 2014

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BackgroundMüller cells, the principal glial cells of the vertebrate retina, are fundamental for the maintenance and function of neuronal cells. In most vertebrates, including humans, Müller cells abundantly express Kir4.1 inwardly rectifying potassium channels responsible for hyperpolarized membrane potential and for various vital functions such as potassium buffering and glutamate clearance; inter-species differences in Kir4.1 expression were, however, observed. Localization and function of potassium channels in Müller cells from the retina of crocodiles remain, hitherto, unknown.MethodsWe studied retinae of the Spectacled caiman (Caiman crocodilus fuscus), endowed with both diurnal and nocturnal vision, by (i) immunohistochemistry, (ii) whole-cell voltage-clamp, and (iii) fluorescent dye tracing to investigate K+ channel distribution and glia-to-neuron communications.ResultsImmunohistochemistry revealed that caiman Müller cells, similarly to other vertebrates, express vimentin, GFAP, S100β, and glutamine synthetase. In contrast, Kir4.1 channel protein was not found in Müller cells but was localized in photoreceptor cells. Instead, 2P-domain TASK-1 channels were expressed in Müller cells. Electrophysiological properties of enzymatically dissociated Müller cells without photoreceptors and isolated Müller cells with adhering photoreceptors were significantly different. This suggests ion coupling between Müller cells and photoreceptors in the caiman retina. Sulforhodamine-B injected into cones permeated to adhering Müller cells thus revealing a uni-directional dye coupling.ConclusionOur data indicate that caiman Müller glial cells are unique among vertebrates studied so far by predominantly expressing TASK-1 rather than Kir4.1 K+ channels and by bi-directional ion and uni-directional dye coupling to photoreceptor cells. This coupling may play an important role in specific glia-neuron signaling pathways and in a new type of K+ buffering.

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Section: Methodsmentioning

confidence: 99%

Unidirectional Photoreceptor-to-Müller Glia Coupling and Unique K+ Channel Expression in Caiman Retina

et al. 2014

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“…RGCs, as well as astrocytes, are filled with the PAs spermine and spermidine. 23, 24, 25 There is one surprising function of RGCs that was recently discovered which is that in the adult retina RGCs provide photon signaling and serve as light guiding fibers 26, 27 .…”

Section: Glia Versus Neuronsmentioning

confidence: 99%

“…1) and their distribution is clearly evolutionarily determined; it is found throughout the brain 23 , retina 24, 25 , peripheral nervous system 59 and in glial-neuronal co-cultures 60 of multiple species, including man 24 . This phenomenon raises key questions: (i) What are the mechanisms that underlie such uneven distribution, accumulation and release from glia?…”

Section: Interaction Of Polyamines With Receptors and Ion Channelsmentioning

confidence: 99%

The Role of Glia in Stress

Skatchkov

Woodbury-Fariña

Eaton

2014

Psychiatric Clinics of North America

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Synopsis This review focuses on the roles of glia and polyamines (PAs) in brain function and dysfunction, highlighting how PAs are one of the principal differences between glia and neurons as they are surprisingly stored, but not synthesized, almost exclusively in glial cells from which they can be released to regulate neuronal synaptic activity. The review includes the novel role of PAs, such as putrescine (PUT), spermidine (SPD) and spermine (SPM) and their precursors and derivatives. However: (i) PAs have not yet been a focus of much glial research; (ii) PAs affect many neuronal and glial receptors, channels and transporters; (iii) PAs are therefore key elements in the development of many diseases and syndromes (iv) thus forming the rationale for PA and glia focused therapy for these conditions.

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“…At least two roles have been identified for polyamines in retinal cells. One is the migration of retinal pigment epithelial cells (Johnson et al, 2002) and the other the regulation of inward-rectifying K+ channels in retinal glial cells (Biedermann et al, 1998). The second phenomenon is also described for inward-rectifying K+ channels in other cell types (Oliver et al, 2000).…”

Section: Expression Of Azr In Developing Zebrafishmentioning

confidence: 99%

Novel antizyme gene in Danio rerio expressed in brain and retina

Ivanov

Pittman

Chien

et al. 2007

Gene

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Spermine/spermidine is expressed by retinal glial (müller) cells and controls distinct K ⁺ channels of their membrane

Cited by 66 publications

References 50 publications

Unidirectional Photoreceptor-to-Müller Glia Coupling and Unique K+ Channel Expression in Caiman Retina

Unidirectional Photoreceptor-to-Müller Glia Coupling and Unique K+ Channel Expression in Caiman Retina

The Role of Glia in Stress

Novel antizyme gene in Danio rerio expressed in brain and retina

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Spermine/spermidine is expressed by retinal glial (müller) cells and controls distinct K + channels of their membrane

Cited by 66 publications

References 50 publications

Unidirectional Photoreceptor-to-Müller Glia Coupling and Unique K+ Channel Expression in Caiman Retina

Unidirectional Photoreceptor-to-Müller Glia Coupling and Unique K+ Channel Expression in Caiman Retina

The Role of Glia in Stress

Novel antizyme gene in Danio rerio expressed in brain and retina

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Product

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Spermine/spermidine is expressed by retinal glial (müller) cells and controls distinct K ⁺ channels of their membrane