Related Experiment Video
Updated: Mar 10, 2026
08:54
Immunohistochemical and Calcium Imaging Methods in Wholemount Rat Retina
Published on: October 13, 2014
15.2K
Contribution of Nav1.8 sodium channels to retinal function
Benjamin J Smith1, Patrice D Côté2, François Tremblay3
1Department of Biology, Dalhousie University, 1355 Oxford St., PO Box 15000, Halifax, NS B3H 4R2, Canada.
Neuroscience
|December 17, 2016
Summary
The sodium channel Nav1.8 significantly impacts retinal function by reducing oscillatory potentials (OPs), suggesting starburst amacrine cells (SBACs) are key contributors to this electroretinogram component.
Area of Science:
- Neuroscience
- Ophthalmology
- Electrophysiology
Background:
- The sodium channel isoform Nav1.8 is expressed in specific retinal neurons.
- Its precise role in retinal function, particularly in electroretinogram (ERG) components beyond the b-wave, remains unclear.
Purpose of the Study:
- To investigate the contribution of Nav1.8 to retinal function using a specific blocker.
- To elucidate the cellular mechanisms underlying Nav1.8's effects on retinal signaling and ERG components.
Main Methods:
- Utilized the specific Nav1.8 blocker A803467 to assess its impact on ERG.
- Recorded light responses from retinal ganglion cells (RGCs) using a multielectrode array (MEA).
- Investigated the role of starburst amacrine cells (SBACs) by targeting them with ethylcholine mustard aziridinium (AF64A).
Main Results:
- A803467 significantly reduced ERG oscillatory potentials (OPs) amplitude by 40-60% with altered implicit times.
- Nav1.8 blockade caused opposing effects on ON-sustained (decrease) and ON-OFF transient (increase) RGCs.
- Targeting SBACs with AF64A mimicked the OP reduction observed with A803467.
Conclusions:
- Nav1.8 plays a crucial role in modulating specific aspects of retinal physiology, particularly OPs.
- Starburst amacrine cells (SBACs) are identified as a fundamental cellular contributor to mouse retinal OPs.
- Highlights a functional dichotomy between ERG b-waves and OPs in the mouse retina.
Related Concept Videos
01:26Voltage-gated Ion Channels
12.2K
Voltage-gated ion channels are transmembrane proteins that open and close in response to changes in the membrane potential. They are present on the membranes of all electrically excitable cells such as neurons, heart, and muscle cells.
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several types of...
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several types of...
12.2K
01:32The Retina
78.1K
The retina is a layer of nervous tissue at the back of the eye that transduces light into neural signals. This process, called phototransduction, is carried out by rod and cone photoreceptor cells in the back of the retina.
78.1K
01:19The Role of Ion Channels in Neuronal Computation
4.1K
A postsynaptic neuron usually receives numerous impulses from several other presynaptic neurons. The axon hillock of the postsynaptic neuron integrates all these signals and determines the likelihood of firing an action potential.
Sometimes a single EPSP is strong enough to induce an action potential in the postsynaptic neuron. However, multiple presynaptic inputs must often create EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential....
Sometimes a single EPSP is strong enough to induce an action potential in the postsynaptic neuron. However, multiple presynaptic inputs must often create EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential....
4.1K
01:11Channel Rhodopsins
3.4K
Most organisms use photoreceptors to sense and respond to light. Examples of photoreceptors include bacteriorhodopsins and bacteriophytochromes in some bacteria, phytochromes in plants, and rhodopsins in the photoreceptor cells of the vertebral retina. The light-sensitive property of these receptors is because of the bound chromophores, such as bilin in the phytochromes and retinal in the rhodopsins.
Rhodopsins belong to the family of cell surface proteins called G-protein coupled receptors,...
Rhodopsins belong to the family of cell surface proteins called G-protein coupled receptors,...
3.4K
01:20Anatomy of the Eyeball
11.1K
The eye is a spherical, hollow structure composed of three tissue layers. The outer layer — the fibrous tunic, comprises the sclera — a white structure — and the cornea, which is transparent. The sclera encompasses some of the ocular surface, most of which is not visible. However, the 'white of the eye' is distinctively visible in humans compared to other species. The cornea, a clear covering at the front of the eye, enables light penetration. The eye's middle...
11.1K