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Updated: Jul 31, 2026
14:33
The Subventricular Zone En-face: Wholemount Staining and Ependymal Flow
Published on: May 6, 2010
Aqueous diffusion pathways as a part of the ventricular cell ultrastructure
A S Parfenov1, V Salnikov, W J Lederer
1Medical Biotechnology Center, University of Maryland Biotechnology Institute, Baltimore, Maryland, USA.
Biophysical Journal
|November 15, 2005
Summary
Ventricular myocytes have size barriers limiting diffusion. Only particles 11 nm or smaller can access the transverse-axial tubular system (TATS) and sarcoplasm, impacting cellular physiology.
Area of Science:
- Cellular Physiology
- Biophysics
- Molecular Biology
Background:
- Ventricular myocytes possess complex internal structures that restrict molecular and particle movement.
- Understanding diffusion limitations is crucial for cellular function and drug delivery.
- Aqueous diffusion pathways within cardiomyocytes present unique size constraints.
Purpose of the Study:
- To investigate the size limitations of aqueous diffusion pathways in ventricular myocytes.
- To determine the accessibility of the transverse-axial tubular system (TATS) and sarcoplasm to nanoparticles.
- To elucidate the impact of diffusion barriers on cellular physiology.
Main Methods:
- Utilized calibrated gold nanoparticles to probe diffusion pathways.
- Examined nanoparticle accessibility in permeabilized ventricular cells.
- Analyzed nanoparticle distribution within the TATS, sarcoplasm, and intracellular structures.
Main Results:
- The TATS and sarcoplasm are accessible only to particles ≤11 nm.
- Intercellular spaces (T-tubule/jSR, jSR/mitochondria, intermitochondrial) are restricted to particles >3 nm.
- Mitochondrial voltage-dependent anion channel and nuclear pore complex permit entry of particles ≥6 nm.
- Distinct size selectivity exists between transversal and longitudinal sarcoplasmic diffusion pathways.
Conclusions:
- Cardiomyocyte diffusion pathways exhibit significant size selectivity, impacting molecular transport.
- Nanoparticle size is a critical determinant for accessing intracellular compartments within ventricular myocytes.
- These findings have implications for understanding cellular function and developing targeted intracellular therapies.
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