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The ultrastructure of patch-clamped membranes: a study using high voltage electron microscopy
A Ruknudin1, M J Song, F Sachs
1Department of Biophysical Sciences, State University of New York, Buffalo 14214.
The Journal of Cell Biology
|January 1, 1991
Summary
High voltage electron microscopy (HVEM) reveals patch-clamped cell membranes are complex cytoplasmic blebs, not bare bilayers. This technique allows detailed study of cell surface structures and receptor distribution.
Area of Science:
- Cell Biology
- Microscopy Techniques
- Biophysics
Background:
- Patch-clamp electrophysiology is a crucial technique for studying ion channels and cellular membrane properties.
- Traditional methods often lack the resolution to fully elucidate the complex structure of the patch itself.
Purpose of the Study:
- To develop and apply high voltage electron microscopy (HVEM) for detailed structural analysis of patch-clamped cell membranes.
- To investigate the composition and organization of membrane patches, including associated cytoplasmic components.
Main Methods:
- Rapid freezing and freeze-drying of pipette tips to preserve patch structure.
- Utilizing high voltage electron microscopy (HVEM) for imaging.
- Employing colloidal gold labeling for identifying specific membrane proteins like acetylcholine receptors.
Main Results:
- Patch-clamped membranes are confirmed to be cytoplasmic blebs containing organelles and cytoskeleton, not simple bilayers.
- Significant structural variations exist between cell types, with consistent differences observed.
- Receptor distribution (acetylcholine receptors) changes dynamically with cell culture age, from diffuse to densely packed arrays.
Conclusions:
- HVEM provides unprecedented structural detail of patch-clamped membranes.
- The patch pipette is a versatile tool for both electrophysiological recording and sampling of cell surface components.
- Dynamic reorganization of cell surface receptors can be visualized and studied using this integrated approach.