Nav1.1 is predominantly expressed in nodes of Ranvier and axon initial segments.
Aggregation of voltage-gated sodium (Nav) channels in the axon initial segment (AIS) and nodes of Ranvier is essential for the generation and propagation of action potentials. From the three Nav channel isoforms (Nav1.1, Nav1.2 and Nav1.6) expressed in the adult CNS, Nav1.1 appears to play an important function since numerous mutations in its coding sequence cause epileptic syndromes. Yet, its distribution is still controversial. Here we demonstrate for the first time that in the adult CNS Nav1.1 is expressed in nodes of Ranvier throughout the mouse spinal cord and in many brain regions. We identified three populations of nodes: expressing Nav1.1, Nav1.6 or both. We also found Nav1.1 expression concentrated in a proximal AIS subcompartment in spinal cord neurons including 80% of motor neurons and in multiple brain areas. This novel distribution suggests that Nav1.1 is involved in the control of action potential generation and propagation.
Duflocq
Amandine
A
UPMC Univ Paris 06, UMR 7101, Paris, France.
Le Bras
Barbara
B
Bullier
Erika
E
Couraud
François
F
Davenne
Marc
M
D000818:Animals; D000831:Animals, Newborn; D017487:Ankyrins / Q000378:metabolism; D001369:Axons / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D007381:Intermediate Filament Proteins; D008562:Membrane Glycoproteins; D051379:Mice; D009046:Motor Neurons / Q000378:metabolism; D062550:NAV1.1 Voltage-Gated Sodium Channel; D062557:NAV1.6 Voltage-Gated Sodium Channel; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D064531:Peripherins; D011901:Ranvier's Nodes / Q000235:genetics / Q000378:metabolism*; D015222:Sodium Channels / Q000235:genetics / Q000378:metabolism*; D013116:Spinal Cord / Q000166:cytology / Q000378:metabolism
C094681:Ank3 protein, mouse; D017487:Ankyrins; D007381:Intermediate Filament Proteins; D008562:Membrane Glycoproteins; D062550:NAV1.1 Voltage-Gated Sodium Channel; D062557:NAV1.6 Voltage-Gated Sodium Channel; D009419:Nerve Tissue Proteins; D064531:Peripherins; C568249:Scn1a protein, mouse; C491046:Scn8a protein, mouse; D015222:Sodium Channels