Electrical coupling between cells of the insect Aedes albopictus

Area of Science:

• Cell Biology
• Electrophysiology
• Insect Physiology

Background:

• Intercellular junctions facilitate communication and transport between cells.
• Insect cell lines offer model systems for studying fundamental cellular processes.
• Distinguishing between different types of cell junctions is crucial for understanding cellular networks.

Purpose of the Study:

• To investigate and differentiate electrical properties of intercellular junctions in Aedes albopictus C6/36 cells.
• To characterize gap junctions and cytoplasmic bridges using functional criteria.
• To determine the influence of membrane potential and chemical agents on junctional conductance.

Main Methods:

• Utilized a double voltage-clamp technique to measure intracellular current flow and control voltage gradients.
• Assessed junctional conductance (gj) based on its dependence on junctional membrane potential (Vj), non-junctional membrane potential (Vm), and heptanol exposure.
• Analyzed functional criteria to distinguish between gap junctions and cytoplasmic bridges.

Main Results:

• Identified two distinct junction types: gap junctions and cytoplasmic bridges, based on electrical properties.
• Gap junctions exhibited voltage-dependent conductance (Vj and Vm) and were blocked by heptanol.
• Cytoplasmic bridges showed insensitivity to voltage changes and heptanol, with a single-channel conductance of 133 pS for gap junctions.
• Some cell pairs displayed properties suggesting the co-existence of both junction types.

Conclusions:

• Functional electrophysiological criteria effectively differentiate between gap junctions and cytoplasmic bridges in insect cells.
• Gap junctions in Aedes albopictus cells display characteristic voltage sensitivity and heptanol sensitivity.
• Cytoplasmic bridges represent a distinct type of intercellular connection with different electrical properties.