What question did this study set out to answer?

To estimate the density and spatial distribution of sodium channels along the nodal and internodal axonal membrane in mammalian myelinated nerve fibers.

January 1, 1977Proceedings of the National Academy of SciencesOpen Access

Density of sodium channels in mammalian myelinated nerve fibers and nature of the axonal membrane under the myelin sheath.

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Authors

JRJ. M. RitchieGoogle (United States)RRR. B. RogartBrigham and Women's Hospital

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Implication

Radioligand binding assay reveals high sodium channel density at nodes versus internodes in rabbit sciatic nerve, highlighting mechanisms of saltatory conduction.

Key Points

To estimate the density and spatial distribution of sodium channels along the nodal and internodal axonal membrane in mammalian myelinated nerve fibers.
Assayed [3H]saxitoxin binding in intact and homogenized rabbit sciatic nerve preparations to differentiate specific saturable binding from linear nonspecific binding.
Estimated channel density at the nodal membrane and under the myelin sheath using maximum saturable binding capacities and dissociation constants.
Intact nerve exhibited a maximum saturable binding capacity of 19.9 ± 1.9 fmol·mg wet⁻¹ (Kt = 3.4 ± 2.0 nM), while homogenized nerve yielded 19.9 ± 1.5 fmol·mg wet⁻¹ (Kt = 1.3 ± 0.7 nM).
Nodal membranes contained approximately 700,000 sodium channels per node, corresponding to a density of approximately 12,000 channels per μm².
Internodal axonal membrane beneath the myelin sheath was calculated to have no more than roughly 25 sodium channels per μm².

Cite This Study

Ritchie et al. (1977) studied this question.

synapsesocial.com/papers/6a1c0cc44ebd09f3dfa960f7 https://doi.org/10.1073/pnas.74.1.211

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Implication

Radioligand binding assay reveals high sodium channel density at nodes versus internodes in rabbit sciatic nerve, highlighting mechanisms of saltatory conduction.

Density of sodium channels in mammalian myelinated nerve fibers and nature of the axonal membrane under the myelin sheath.

Discussion

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Implication

Key Points

Cite This Study

Density of sodium channels in mammalian myelinated nerve fibers and nature of the axonal membrane under the myelin sheath.

Discussion

Member takes

Implication

Key Points

Cite This Study

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