Related Experiment Video
Updated: Aug 11, 2026
14:18
Fluorescence-based Measurement of Store-operated Calcium Entry in Live Cells: from Cultured Cancer Cell to Skeletal Muscle Fiber
Published on: February 13, 2012
Osmolyte channel regulation by ionic strength in skate RBC
K A Wittels1, E M Hubert, M W Musch
1Division of Biology and Medicine, Brown University, Providence, Rhode Island 02912, USA.
Summary
Intracellular ionic strength influences the taurine channel in skate red blood cells (RBC). A decrease in ionic strength alone does not fully explain taurine efflux, suggesting another regulator is involved.
Area of Science:
- Cellular Physiology
- Membrane Transport
- Biochemistry
Background:
- Skate red blood cells (RBC) possess an osmolyte channel crucial for cell volume regulation.
- Previous research suggests ionic strength impacts this channel's activity.
Purpose of the Study:
- To investigate if intracellular electrolyte concentration and conductivity regulate the osmolyte channel in skate RBC.
- To determine the specific role of ionic strength in taurine channel opening.
Main Methods:
- Inducing cell swelling in skate RBC using both hyposmotic and isosmotic (electrolyte and nonelectrolyte) conditions.
- Measuring taurine efflux from RBC under various osmotic conditions.
- Assaying band 3 phosphorylating enzyme activity in response to swelling stimuli.
Main Results:
- Increased ionic strength inhibited taurine channel opening, consistent with prior studies.
- Decreased ionic strength did not uniformly stimulate taurine efflux; hyposmotic swelling caused greater efflux than nonelectrolyte-induced swelling.
- Band 3 phosphorylating enzyme activity correlated with taurine efflux, showing lower stimulation in nonelectrolyte-swollen cells.
Conclusions:
- A reduction in intracellular ionic strength is not the sole trigger for skate RBC taurine channel opening.
- While ionic strength modulates channel activity, other regulatory factors are implicated.
- The findings highlight a complex regulatory mechanism for osmolyte transport in skate RBC.
More Related Videos
Related Concept Videos
00:59Tonicity in Animals
The tonicity of a solution determines if a cell gains or loses water in that solution. The tonicity depends on the permeability of the cell membrane for different solutes and the concentration of nonpenetrating solutes in the solution within and outside of the cell. If a semipermeable membrane hinders the passage of some solutes but allows water to follow its concentration gradient, water moves from the side with low osmolarity (i.e., less solute) to the side with higher osmolarity (i.e.,...
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...
02:32Osmoregulation in Fishes
When cells are placed in a hypotonic (low-salt) fluid, they can swell and burst. Meanwhile, cells in a hypertonic solution—with a higher salt concentration—can shrivel and die. How do fish cells avoid these gruesome fates in hypotonic freshwater or hypertonic seawater environments?
01:27Feedback Regulation of Calcium Concentration
Calcium is an essential signaling molecule required for various cellular functions. Calcium pumps and ion channels on cell and organellar membranes, such as those on the endoplasmic reticulum (ER), regulate calcium concentrations inside the cell. They remain closed, keeping the cytosolic calcium levels low at a resting state.
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
01:12Ionic Strength: Overview
The ionic strength of a solution is a quantitative way of expressing the total electrolyte concentration of a solution. This concept was first introduced in 1921 by two American physical chemists, Gilbert N. Lewis and Merle Randall, while describing the activity coefficient of strong electrolytes. During the calculation of ionic strength (I or μ), all the cations and anions are considered. However, the concentration (c) of an ion with a greater charge number (z) has a greater contribution to...
01:21Electrochemical Gradient and Channel Proteins: An Overview
An electrochemical gradient is a fundamental concept in biology and chemistry. It regulates the movement of ions across cell membranes. This movement is influenced by two factors:
The electrical gradient: The electrical gradient across cell membranes refers to the difference in electric charge between the inside and outside of a cell. This difference drives the movement of ions towards or away from the cells. For instance, if the inside of the cell is more negatively charged relative to the...
The electrical gradient: The electrical gradient across cell membranes refers to the difference in electric charge between the inside and outside of a cell. This difference drives the movement of ions towards or away from the cells. For instance, if the inside of the cell is more negatively charged relative to the...