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Steady-state current flow through gap junctions. Effects on intracellular ion concentrations and fluid movement
P R Brink1, R T Mathias, S W Jaslove
1Department of Anatomy, State University of New York, Stony Brook 11794.
Biophysical Journal
|May 1, 1988
Summary
Gap junctions in earthworm axons show slow current relaxation due to ion polarization, not direct voltage gating. This suggests electrical currents influence ion distribution and water flow within cells.
Area of Science:
- Neuroscience
- Cell Biology
- Biophysics
Background:
- Gap junctions facilitate direct cell-to-cell communication.
- Understanding their electrical properties is crucial for neural function.
Purpose of the Study:
- To investigate the electrical properties of earthworm median giant axon gap junctions.
- To determine the response of gap junctions to voltage changes.
Main Methods:
- Double voltage clamp technique applied to earthworm median giant axon septal membranes.
- Analysis of transjunctional current and voltage responses.
Main Results:
- Gap junctions showed no conductance change with voltage across membranes.
- A slow (10s) relaxation of trans-septal current was observed under transjunctional voltage steps.
- Evidence suggests relaxation is due to septum polarization from ion accumulation/depletion.
Conclusions:
- Transjunctional currents influence intracellular ion distribution.
- Theoretical analysis indicates these currents drive significant intracellular and intercellular water flow.