Related Experiment Video
Updated: Jun 8, 2026
11:51
Application of Electrophysiology Measurement to Study the Activity of Electro-Neutral Transporters
Published on: February 3, 2018
Diffusion-convection effects on drug distribution at the cell membrane level in a patch-clamp setup
Irina Baran1, Adrian Iftime, Anca Popescu
1Dept. of Biophysics, "Carol Davila" University of Medicine and Pharmacy, 8 Eroilor Sanitari Blvd., Bucharest 050474, Romania. baran@ifin.nipne.ro
Bio Systems
|September 21, 2010
Summary
This study introduces a model to accurately measure drug concentration at the cell membrane during patch-clamp experiments. This method helps explain cell response variability and optimizes drug delivery analysis.
Area of Science:
- Pharmacology
- Biophysics
- Computational Biology
Background:
- Patch-clamp electrophysiology is crucial for studying cell signaling.
- Variability in cellular electric responses can complicate data interpretation.
- Accurate drug concentration at the cell membrane is essential for reliable results.
Purpose of the Study:
- To develop a model-based method for estimating effective drug concentration in patch-clamp experiments.
- To investigate factors contributing to the variability of cellular electric responses.
- To explain and quantitatively reproduce experimental observations in ligand-induced currents.
Main Methods:
- Model-based estimation of drug concentration.
- Finite-difference and finite-element simulations.
- Investigation of diffusion and convection effects on agonist distribution.
Main Results:
- Drug can accumulate between the pipette tip and cell, increasing effective concentration.
- Model explains latency in whole-cell currents and its concentration dependence.
- Bath chamber geometry, pipette tip, and transport parameters influence current amplitude and kinetics.
Conclusions:
- The developed model provides practical utility for analyzing patch-clamp data.
- Accurate estimation of drug concentration is vital for understanding cellular responses.
- Transport phenomena and experimental setup significantly impact electrophysiological measurements.
Related Concept Videos
01:18Patch Clamp
Many fundamental cell functions such as muscle contraction and nerve transmission rely on the electrical signals produced by the movement of positively and negatively charged ions across the cell membrane. One competent method to record current flowing across the whole cell or single ion channel is the patch-clamp technique.
In this method, a glass micropipette containing electrolyte solution is tightly sealed against a small portion of the cell membrane. As a result, a patch of the cell...
In this method, a glass micropipette containing electrolyte solution is tightly sealed against a small portion of the cell membrane. As a result, a patch of the cell...
01:17Passive Diffusion: Overview and Kinetics
Passive diffusion is a critical process that allows small lipophilic drugs to cross the cell membrane along a concentration gradient. This mechanism's efficiency depends on four primary factors: the membrane's surface area, the drug's lipid-water partition coefficient, the concentration gradient, and the membrane's thickness.
When administered orally, drugs establish a substantial concentration gradient between the gastrointestinal (GI) lumen and the bloodstream, expediting their diffusion into...
When administered orally, drugs establish a substantial concentration gradient between the gastrointestinal (GI) lumen and the bloodstream, expediting their diffusion into...
01:23Drug Absorption Mechanism: Passive Membrane Transport
Passive transport is a method of drug absorption where small, lipid-soluble drugs can move across the cell membrane. This movement happens along the concentration gradient, which is a natural flow from higher to lower concentration areas. The speed at which the drug moves is directly related to its lipid–water partition coefficient. This means that the more a drug dissolves in lipids, the faster it diffuses or spreads throughout the body. It is important to note that most drugs are either weak...
00:57Physiological Pharmacokinetic Models: Blood Flow-Limited Versus Diffusion-Limited Models
Physiological pharmacokinetic models, often called flow-limited or perfusion models, typically assume a swift drug distribution between tissue and venous blood, creating a rapid drug equilibrium. This premise is based on the idea that drug diffusion is extremely fast, and the cell membrane presents no barrier to drug permeation. In this scenario, where no drug binding occurs, the drug concentration in the tissue equals that of the venous blood leaving the tissue. This greatly simplifies the...
01:24Cellular Membranes and Drug Transport
Drugs must traverse multiple biological barriers, such as multi-layered skin, single-layered intestinal epithelium, and the plasma membrane, to reach their target sites within the body. The plasma membrane, a highly structured composite of phospholipids, carbohydrates, and proteins, is the cell's protective boundary, facilitating selective substance exchange.
Phospholipids arrange themselves into a bilayer, with hydrophilic heads oriented outward and hydrophobic tails facing inward.
Phospholipids arrange themselves into a bilayer, with hydrophilic heads oriented outward and hydrophobic tails facing inward.
01:24Protein Diffusion in the Membrane
Proteins show rotational as well as lateral diffusion across the membrane. The lateral diffusion of proteins was confirmed through the cell fusion experiment where mouse and human cells were fused, resulting in hybrid cells. When the human and mouse cells fused, the specific membrane proteins on human and mouse cells were marked with the red and green-fluorescent markers, respectively. Initially, the red and green fluorescence was located on the respective hemisphere of the cell. As time...