Related Experiment Video
Updated: Aug 9, 2026
09:12
Channelrhodopsin2 Mediated Stimulation of Synaptic Potentials at Drosophila Neuromuscular Junctions
Published on: March 16, 2009
D2O-induced ion channel activation in Characeae at low ionic strength
P R Andjus1, A A Kataev, A A Alexandrov
1Institute of Cell Biophysics, Russian Academy of Sciences, Puschino, Moscow region.
The Journal of Membrane Biology
|October 1, 1994
Summary
Deuterium oxide (D2O) irreversibly activates calcium (Ca2+) channels in Nitellopsis obtusa, subsequently triggering chloride (Cl-) channels. This effect is dependent on external ion concentration and suggests a mechanism involving osmotic stress or altered hydrogen bonding.
Area of Science:
- Plant Physiology
- Biophysics
- Ion Channel Research
Background:
- The freshwater alga Nitellopsis obtusa possesses ion channels crucial for cellular function.
- Understanding the effects of deuterium oxide (D2O) on these channels can elucidate cellular mechanisms.
Purpose of the Study:
- To investigate the impact of D2O on ion channel activity in Nitellopsis obtusa.
- To explore the underlying mechanisms of D2O's effects on calcium (Ca2+) and chloride (Cl-) channels.
Main Methods:
- Voltage clamp experiments on tonoplast-free internodal cells of Nitellopsis obtusa.
- Reconstitution of isolated Ca2+ channels into bilayer lipid membranes (BLM).
- Perfusion of cells with artificial pond water (APW) containing varying concentrations of D2O.
Main Results:
- External D2O application caused a significant, irreversible drop in membrane resistance, indicating channel activation.
- D2O activated Ca2+ channels, which in turn activated Cl- channels.
- The observed effects were dependent on external ion concentrations and absent with intracellular D2O substitution.
Conclusions:
- D2O acts as an irreversible activator of Ca2+ channels in Nitellopsis obtusa.
- The mechanism may involve osmotic-like stress or increased D-bond energy compared to H-bonds.
- These findings provide insights into ion channel regulation and the biophysical effects of D2O.
More Related Videos
Related Concept Videos
00:53Tonicity in Plants
Tonicity describes the capacity of a cell to lose or gain water. It depends on the quantity of solute that does not penetrate the membrane. Tonicity delimits the magnitude and direction of osmosis and results in three possible scenarios that alter the volume of a cell: hypertonicity, hypotonicity, and isotonicity. Due to differences in structure and physiology, tonicity of plant cells is different from that of animal cells in some scenarios.Plants and Hypotonic EnvironmentsUnlike animal cells,...
01:19Ion Channels
The movement of ions like sodium, potassium, and calcium into and out of the cell is essential to maintain the electrochemical gradient in living cells. The ion channels—a class of membrane transport proteins—help maintain this ionic gradient for the smooth functioning of physiological activities such as maintaining cell size and volume, conducting nerve impulses, and gas and nutrient exchange.
Ion channels are specialized integral membrane proteins on the plasma membrane that allow specific...
Ion channels are specialized integral membrane proteins on the plasma membrane that allow specific...
01:24Non-gated Ion Channels
Ion channels are specialized proteins on the plasma membrane that allow charged ions to pass down their electrochemical gradient. Their main function is to maintain the membrane potential which is critical for cell viability. These channels are either gated or non-gated and can transport more than a thousand ions within milliseconds for the cellular event to occur.
Compared to the gated ion channels, the non-gated channels, also known as leakage or passive channels, have no gating mechanism.
Compared to the gated ion channels, the non-gated channels, also known as leakage or passive channels, have no gating mechanism.
01:12Mechanically-gated Ion Channels
Mechanically-gated ion channels are proteins found in eukaryotic and prokaryotic cell membranes that open in response to mechanical stress. Tension, compression, swelling, and shear stress can alter the conformation of the protein, opening a transmembrane channel that allows the passage of ions for signal transmission. In eukaryotes, mechanically-gated channels are distributed in several regions like the neurons, lungs, skin, bladder, and heart, where they play critical roles in numerous...
01:20Tonicity in Plants
Plant cells maintain appropriate osmotic balance in extreme conditions. For instance, plants in dry environments store water in vacuoles, limit the opening of their stoma, and have thick, waxy cuticles to prevent unnecessary water loss. Some species of plants that live in salty environments store salt in their roots. As a result, water osmosis occurs in the root from the surrounding soil.
Tonicity
Tonicity describes the capacity of a cell to lose or gain water depending on the solute...
Tonicity
Tonicity describes the capacity of a cell to lose or gain water depending on the solute...
01:24Non-gated Ion Channels
Ion channels are specialized proteins on the plasma membrane that allow charged ions to pass down their electrochemical gradient. Their main function is to maintain the membrane potential which is critical for cell viability. These channels are either gated or non-gated and can transport more than a thousand ions within milliseconds for the cellular event to occur.
Compared to the gated ion channels, the non-gated channels, also known as leakage or passive channels, have no gating mechanism.
Compared to the gated ion channels, the non-gated channels, also known as leakage or passive channels, have no gating mechanism.