Physiological Maturation of Photoreceptors Depends on the Voltage-Gated Sodium Channel NaV1.6 (Scn8a)

Voltage-gated sodium channels (VGSCs) ensure the saltatory propagation of action potentials along axons by acting as signal amplifiers at the nodes of Ranvier. In the retina, activity mediated by VGSCs is important for the refinement of the retinotectal map. Here, we conducted a full-field electrore...

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Bibliographic Details
Published in:The Journal of neuroscience 2005-05, Vol.25 (20), p.5046-5050
Main Authors: Cote, Patrice D, De Repentigny, Yves, Coupland, Stuart G, Schwab, Yannick, Roux, Michel J, Levinson, S. Rock, Kothary, Rashmi
Format: Article
Language:English
Subjects:
Animals
Animals, Newborn
Brief Communications
Dose-Response Relationship, Radiation
Electroretinography - methods
Gene Expression Regulation, Developmental - genetics
Gene Expression Regulation, Developmental - physiology
Life Sciences
Mice
Mice, Inbred C57BL
Mice, Knockout
Microscopy, Electron, Transmission - methods
NAV1.6 Voltage-Gated Sodium Channel
Nerve Tissue Proteins - deficiency
Nerve Tissue Proteins - physiology
Neurons and Cognition
Photic Stimulation - methods
Photoreceptor Cells - growth & development
Photoreceptor Cells - physiology
Photoreceptor Cells - radiation effects
Photoreceptor Cells - ultrastructure
Sodium Channels - deficiency
Sodium Channels - physiology
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Summary:Voltage-gated sodium channels (VGSCs) ensure the saltatory propagation of action potentials along axons by acting as signal amplifiers at the nodes of Ranvier. In the retina, activity mediated by VGSCs is important for the refinement of the retinotectal map. Here, we conducted a full-field electroretinogram (ERG) study on mice null for the sodium channel NaV1.6. Interestingly, the light-activated hyperpolarization of photoreceptor cells (the a-wave) and the major "downstream" components of the ERG, the b-wave and the oscillatory potentials, are markedly reduced and delayed in these mice. The functional deficit was not associated with any morphological abnormality. We demonstrate that Scn8a is expressed in the ganglion and inner nuclear layers and at low levels in the outer nuclear layer beginning shortly before the observed ERG deficit. Together, our data reveal a previously unappreciated role for VGSCs in the physiological maturation of photoreceptors.
ISSN:0270-6474
1529-2401
DOI:10.1523/JNEUROSCI.4692-04.2005