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A voltage-dependent gap junction in Drosophila melanogaster.
V K Verselis1, M V Bennett, T A Bargiello
1Albert Einstein College of Medicine, Bronx, New York 10461.
Biophysical Journal
|January 1, 1991
Summary
Drosophila salivary gland gap junctions show complex voltage dependence. Two distinct voltages, transjunctional (Vj) and inside-outside (Vi,o), interact to control conductance (gj) through unique gating mechanisms.
Area of Science:
- Cellular physiology
- Ion channel biophysics
- Drosophila melanogaster research
Background:
- Gap junctions mediate intercellular communication in salivary glands.
- Understanding gap junction voltage dependence is crucial for cellular function.
Purpose of the Study:
- To analyze the steady-state and kinetic properties of gap junctional conductance (gj) in Drosophila salivary glands.
- To investigate the complex voltage dependence of gap junctions under different voltage conditions.
Main Methods:
- Performed steady-state and kinetic analyses of gap junctional conductance (gj).
- Applied transjunctional voltages (Vj) and inside-outside voltages (Vi,o) to salivary gland cells.
- Utilized electrophysiological techniques to measure conductance changes.
Main Results:
- Inside-outside voltages (Vi,o) showed a voltage-dependent increase in gj upon hyperpolarization and decrease upon depolarization, fitting a two-gate model.
- Transjunctional voltages (Vj) significantly reduced gj with complex kinetics dependent on both Vj and Vi,o.
- A two-phase response to Vj was observed at positive Vi,o: an early gj decrease and a later phase dependent on hyperpolarization/depolarization.
Conclusions:
- Gap junction channels in Drosophila salivary glands exhibit two distinct, interactive forms of voltage dependence.
- The gating mechanisms for Vi,o and Vj appear to be different, suggesting complex regulation of intercellular communication.