Ionic currents ofdrosophila embryonic neurons derived from selectively cultured CNS midline precursors

Schmidt, Hartmut; Lüer, Karin; Hevers, Wulf; Technau, Gerhard M.

doi:10.1002/1097-4695(20000915)44:4<392::aid-neu3>3.0.co;2-m

Cited by 21 publications

(2 citation statements)

References 76 publications

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“…In Drosophila CNS precursors, the expression of K v currents seemed to be cell autonomous, while other currents changed, when cell-cell contacts occurred [14]. Therefore, potassium channel function is assumed to be a key requirement for proper progenitor cell proliferation and also may pave the way for neuronal differentiation [15]–[17].…”

Section: Introductionmentioning

confidence: 99%

“…Early functional investigations pointed out that I A is typically involved in setting the interspike interval [22], while I DR is essential for fast repolarization of action potentials and consequently contributes to repetitive firing [22], [26]. Biophysical separation of these two currents can be obtained by the design of appropriate voltage protocols [14], [27]. However, due to the diversity of K v channels additional pharmacological isolation of current components is often required [25].…”

Section: Introductionmentioning

confidence: 99%

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Characterization of Voltage-Gated Potassium Channels in Human Neural Progenitor Cells

et al. 2009

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BackgroundVoltage-gated potassium (Kv) channels are among the earliest ion channels to appear during brain development, suggesting a functional requirement for progenitor cell proliferation and/or differentiation. We tested this hypothesis, using human neural progenitor cells (hNPCs) as a model system.Methodology/Principal FindingsIn proliferating hNPCs a broad spectrum of Kv channel subtypes was identified using quantitative real-time PCR with a predominant expression of the A-type channel Kv4.2. In whole-cell patch-clamp recordings Kv currents were separated into a large transient component characteristic for fast-inactivating A-type potassium channels (IA) and a small, sustained component produced by delayed-rectifying channels (IK). During differentiation the expression of IA as well as A-type channel transcripts dramatically decreased, while IK producing delayed-rectifiers were upregulated. Both Kv currents were differentially inhibited by selective neurotoxins like phrixotoxin-1 and α-dendrotoxin as well as by antagonists like 4-aminopyridine, ammoniumchloride, tetraethylammonium chloride and quinidine. In viability and proliferation assays chronic inhibition of the A-type currents severely disturbed the cell cycle and precluded proper hNPC proliferation, while the blockade of delayed-rectifiers by α-dendrotoxin increased proliferation.Conclusions/SignificanceThese findings suggest that A-type potassium currents are essential for proper proliferation of immature multipotent hNPCs.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Characterization of Voltage-Gated Potassium Channels in Human Neural Progenitor Cells

et al. 2009

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Ultrastructural analysis of chemical synapses and gap junctions between Drosophila brain neurons in culture

Campusano

Hilgenberg

et al. 2007

Developmental Neurobiology

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Dissociated cultures from many species have been important tools for exploring factors that regulate structure and function of central neuronal synapses. We have previously shown that cells harvested from brains of late stage Drosophila pupae can regenerate their processes in vitro. Electrophysiological recordings demonstrate the formation of functional synaptic connections as early as 3 days in vitro (DIV), but no information about synapse structure is available. Here, we report that antibodies against pre-synaptic proteins Synapsin and Bruchpilot result in punctate staining of regenerating neurites. Puncta density increases as neuritic plexuses develop over the first 4 DIV. Electron microscopy reveals that closely apposed neurites can form chemical synapses with both pre- and postsynaptic specializations characteristic of many inter-neuronal synapses in the adult brain. Chemical synapses in culture are restricted to neuritic processes and some neurite pairs form reciprocal synapses. GABAergic synapses have a significantly higher percentage of clear core versus granular vesicles than non-GABA synapses. Gap junction profiles, some adjacent to chemical synapses, suggest that neurons in culture can form purely electrical as well as mixed synapses, as they do in the brain. However, unlike adult brain, gap junctions in culture form between neuronal somata as well as neurites, suggesting soma ensheathing glia, largely absent in culture, regulate gap junction location in vivo. Thus pupal brain cultures, which support formation of interneuronal synapses with structural features similar to synapses in adult brain, are a useful model system for identifying intrinsic and extrinsic regulators of central synapse structure as well as function.

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Olfactory receptor axons influence the development of glial potassium currents in the antennal lobe of the moth Manduca sexta

Lohr

Oland

Tolbert

2001

Glia

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In the olfactory (antennal) lobe of the moth Manduca sexta, olfactory receptor axons strongly influence the distribution and morphology of glial cells. In the present study, we asked whether the development of the electrophysiological properties of the glial cells is influenced by the receptor axons. Whole-cell currents were measured in antennal lobe glial cells in acute brain slices prepared from animals at different stages of metamorphic development (stages 3, 6, and 12). Outward currents were induced by depolarizing voltage steps from a holding potential of -70 mV. At all developmental stages investigated, the outward currents were partly blocked by bath application of the potassium channel blocker 4-aminopyridine (4AP, 10 mM) or by including tetraethylammonium (TEA, 30 mM) in the pipette solution. The relative contribution of the 4AP-sensitive current to the outward current increased from 18% at stages 3 and 6 to 42% at stage 12, while the TEA-sensitive current increased from 18% at stage 3 to 81% at stage 6, and then declined again to 40% at stage 12. In contrast, in the absence of receptor axons, these changes in the contribution of the TEA- and 4AP-sensitive currents to the total outward current did not occur; rather, the current profile remained in the most immature state (stage 3). The results suggest that olfactory receptor axons are essential for development of the mature pattern of glial potassium currents.

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Ionic currents ofdrosophila embryonic neurons derived from selectively cultured CNS midline precursors

Cited by 21 publications

References 76 publications

Characterization of Voltage-Gated Potassium Channels in Human Neural Progenitor Cells

Characterization of Voltage-Gated Potassium Channels in Human Neural Progenitor Cells

Ultrastructural analysis of chemical synapses and gap junctions between Drosophila brain neurons in culture

Olfactory receptor axons influence the development of glial potassium currents in the antennal lobe of the moth Manduca sexta

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