Action of benzocaine on sodium channels of frog nodes of ranvier treated with chloramine-T

1987 ◽  
Vol 409 (3) ◽  
pp. 265-273 ◽  
Author(s):  
T. Meeder ◽  
W. Ulbricht
Keyword(s):  
Sodium Channels ◽  
Nodes Of Ranvier ◽  
Chloramine T

scholarly journals Nodes of Ranvier and axon initial segments are ankyrin G–dependent domains that assemble by distinct mechanisms

2007 ◽  
Vol 177 (5) ◽  
pp. 857-870 ◽  
Author(s):  
Yulia Dzhashiashvili ◽  
Yanqing Zhang ◽  
Jolanta Galinska ◽  
Isabel Lam ◽  
Martin Grumet ◽  
...  
Keyword(s):  
Schwann Cells ◽  
Sodium Channels ◽  
Cytoskeletal Proteins ◽  
Action Potential Generation ◽  
Potential Generation ◽  
Nodes Of Ranvier ◽  
Ankyrin G ◽  
Sites Of Action ◽  
Axon Initial Segments ◽  
Inside Out

Axon initial segments (AISs) and nodes of Ranvier are sites of action potential generation and propagation, respectively. Both domains are enriched in sodium channels complexed with adhesion molecules (neurofascin [NF] 186 and NrCAM) and cytoskeletal proteins (ankyrin G and βIV spectrin). We show that the AIS and peripheral nervous system (PNS) nodes both require ankyrin G but assemble by distinct mechanisms. The AIS is intrinsically specified; it forms independent of NF186, which is targeted to this site via intracellular interactions that require ankyrin G. In contrast, NF186 is targeted to the node, and independently cleared from the internode, by interactions of its ectodomain with myelinating Schwann cells. NF186 is critical for and initiates PNS node assembly by recruiting ankyrin G, which is required for the localization of sodium channels and the entire nodal complex. Thus, initial segments assemble from the inside out driven by the intrinsic accumulation of ankyrin G, whereas PNS nodes assemble from the outside in, specified by Schwann cells, which direct the NF186-dependent recruitment of ankyrin G.

Effects of chloramine-T on activation and inactivation of sodium channels in neuroblastoma cells

1988 ◽  
Vol 19 (6) ◽  
pp. 574-579 ◽  
Author(s):  
E. D. Nosyreva ◽  
I. I. Grishchenko ◽  
Yu. A. Negulyaev
Keyword(s):  
Sodium Channels ◽  
Neuroblastoma Cells ◽  
Chloramine T

scholarly journals Differential Control of Clustering of the Sodium Channels Nav1.2 and Nav1.6 at Developing CNS Nodes of Ranvier

Neuron ◽  
2001 ◽  
Vol 30 (1) ◽  
pp. 105-119 ◽  
Author(s):  
Miriam R Kaplan ◽  
Min-Hee Cho ◽  
Erik M Ullian ◽  
Lori L Isom ◽  
S.Rock Levinson ◽  
...  
Keyword(s):  
Sodium Channels ◽  
Nodes Of Ranvier ◽  
Differential Control

scholarly journals βIVΣ1 spectrin stabilizes the nodes of Ranvier and axon initial segments

2004 ◽  
Vol 166 (7) ◽  
pp. 983-990 ◽  
Author(s):  
Sandra Lacas-Gervais ◽  
Jun Guo ◽  
Nicola Strenzke ◽  
Eric Scarfone ◽  
Melanie Kolpe ◽  
...  
Keyword(s):  
Sodium Channels ◽  
Actin Binding ◽  
Ultrastructural Changes ◽  
Nodes Of Ranvier ◽  
Ankyrin G ◽  
Voltage Gated Sodium Channels ◽  
Dense Membrane ◽  
Afferent Fibers ◽  
Actin Binding Domain ◽  
Axon Initial Segments

Saltatory electric conduction requires clustered voltage-gated sodium channels (VGSCs) at axon initial segments (AIS) and nodes of Ranvier (NR). A dense membrane undercoat is present at these sites, which is thought to be key for the focal accumulation of channels. Here, we prove that βIVΣ1 spectrin, the only βIV spectrin with an actin-binding domain, is an essential component of this coat. Specifically, βIVΣ1 coexists with βIVΣ6 at both AIS and NR, being the predominant spectrin at AIS. Removal of βIVΣ1 alone causes the disappearance of the nodal coat, an increased diameter of the NR, and the presence of dilations filled with organelles. Moreover, in myelinated cochlear afferent fibers, VGSC and ankyrin G clusters appear fragmented. These ultrastructural changes can explain the motor and auditory neuropathies present in βIVΣ1 −/− mice and point to the βIVΣ1 spectrin isoform as a master-stabilizing factor of AIS/NR membranes.

Immuno-ultrastructural localization of sodium channels at nodes of Ranvier and perinodal astrocytes in rat optic nerve

1989 ◽  
Vol 238 (1290) ◽  
pp. 39-51 ◽  
Keyword(s):  
Optic Nerve ◽  
Sodium Channel ◽  
Sodium Channels ◽  
Node Of Ranvier ◽  
Ultrastructural Localization ◽  
Active Role ◽  
Nodes Of Ranvier ◽  
Electron Microscopic ◽  
Axon Membrane ◽  
Intense Immunoreactivity

Immuno-electron microscopic localization of sodium channels at nodes of Ranvier within adult optic nerve was demonstrated with polyclonal antibody 7493. The 7493 antisera, which is directed against purified sodium channels from rat brain, recognizes a 260 kDa protein in immunoblots of the crude glycoprotein fraction from adult rat optic nerve. Intense immunoreactivity with 7493 antisera was observed at nodes of Ranvier. Axon membrane at the node was densely stained, whereas paranodal and internodal axon membrane did not exhibit immunoreactivity. The axoplasm beneath the nodal membrane displayed variable immunostaining. Neither terminal paranodal oligodendroglial loops nor oligodendrocyte plasmalemma were immunoreactive with 7493 antisera. However, perinodal astrocyte processes exhibited intense immunoreactivity with the anti-sodium channel antisera. Optic nerves incubated with pre-immune sera, or with 7493 antisera that had been pre-adsorbed with purified sodium channel protein, displayed no immunoreactivity. These results demonstrate localization of sodium channels at high density at mammalian nodes of Ranvier and in some perinodal astrocyte processes. The latter observation offers support for an active role for perinodal astrocyte processes in the aggregation of sodium channels within the axon membrane at the node of Ranvier.

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