# Ion channels and their functions at the node of Ranvier of mammalian somatosensory afferent fibers

> **NIH NIH R01** · UNIVERSITY OF ALABAMA AT BIRMINGHAM · 2022 · $400,034

## Abstract

Nodes of Ranvier are highly specialized axonal regions on myelinated nerve fibers of sensory, motor and
central nervous systems where action potentials are propagated by saltatory (leap in Latin word) conduction.
Saltatory conduction through nodes of Ranvier ensures timely sensory and motor responses and precise signal
processing in the CNS. A number of neurological diseases affect nodes of Ranvier to impair saltatory
conduction leading to motor disorders, such as paralysis and sensory dysfunctions, such as pain, numbness,
and other abnormal sensations. Knowledge of ion channels and their functions at mammalian nodes of Ranvier
is a key to fully understanding saltatory conduction under both physiological and pathological conditions, and
for potential treatments of those sensory and motor disorders. The overall goal of this project is to study ion
channel mechanisms for securing saltatory conduction of action potentials at mammalian nodes of Ranvier.
We have recently developed the in situ patch-clamp recording technique for nodes of Ranvier in
somatosensory afferent fibers of rats. In the preliminary studies we have found that nodes of Ranvier express
surprisingly high levels of the two-pore domain potassium channels (K2P channels), a unique family of ion
channels that constitutively open, and the function of which, in action potentials, as well as in nerve conduction
was previously unknown. Functionally, our preliminary studies strongly suggest that K2P channels are key
molecules for securing saltatory conduction in myelinated somatosensory afferent fibers of mammals. In this
application, we will use the in situ patch-clamp recording technique in conjunction with pharmacology, gene
knockdown, and immunochemistry approaches to achieve the following specific aims. Aim 1. Characterize
K2P channels and elucidate their molecular identities at the node of Ranvier of rat somatosensory
afferent fibers. In this aim we will pin down K2P channel subtypes at the node of Ranvier and profile their
pharmacological and single channel properties. Aim 2. Study specific roles of K2P channels in securing
saltatory conduction at the node of Ranvier of rat somatosensory afferent fibers. This aim will elucidate
that the K2P channels at the node of Ranvier play a key role in rapid action potential repolarization and in
securing high speed and high frequency saltatory conduction. Aim 3. Elucidate that K2P channels at the
node of Ranvier play a key role in temperature-dependent saltatory conduction on rat somatosensory
afferent fibers. This aim will test the idea that K2P channels at the node of Ranvier are highly thermal
sensitive, which is a determinant factor controlling the velocity and fidelity of saltatory conduction at different
temperatures. This aim exemplifies that biological factors affecting K2P channel activity will highly impact
saltatory conductions in myelinated nerve fibers. Completion of the 3 Aims will elucidate a novel ion channel
mechanism that secure...

## Key facts

- **NIH application ID:** 10322385
- **Project number:** 5R01NS109059-04
- **Recipient organization:** UNIVERSITY OF ALABAMA AT BIRMINGHAM
- **Principal Investigator:** JIANGUO GU
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $400,034
- **Award type:** 5
- **Project period:** 2019-01-01 → 2023-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10322385

## Citation

> US National Institutes of Health, RePORTER application 10322385, Ion channels and their functions at the node of Ranvier of mammalian somatosensory afferent fibers (5R01NS109059-04). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10322385. Licensed CC0.

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