Determination of gap junctional intercellular communication by capacitance measurements

Area of Science:

• Cell Biology
• Biophysics
• Physiology

Background:

• Electrical coupling is crucial for cell-to-cell communication.
• Traditional double-patch-clamp methods are limited to paired cells.
• A novel technique is needed to study coupling in cell clusters.

Purpose of the Study:

• To develop and validate a single patch-clamp technique for measuring electrical coupling in cell clusters.
• To assess intercellular communication in normal rat kidney (NRK) fibroblasts using capacitance measurements.
• To investigate the effects of gap junction inhibitors and a tumor promoter on electrical coupling.

Main Methods:

• Utilized whole-cell patch-clamp configuration on NRK fibroblast clusters.
• Evoked capacitive transients with small voltage pulses to calculate total membrane capacitance.
• Determined access resistance, membrane conductance, and decay constants for capacitance calculation.

Main Results:

• Membrane capacitance increased linearly with cell number in clusters (1-10 cells), indicating electrical coupling.
• Increased membrane conductance was observed in coupled cell clusters.
• Gap junction inhibitors (halothane, heptanol, octanol) and TPA completely uncoupled cells, reducing capacitance to single-cell levels.

Conclusions:

• Capacitance measurements using a single patch-clamp technique effectively quantify electrical coupling in cell clusters.
• This method provides a valuable tool for studying changes in intercellular communication.
• The study demonstrates the impact of specific agents on gap junction-mediated communication.