Instantaneous inward rectification in the Mauthner cell: a postsynaptic booster for excitatory inputs.

Area of Science:

• Neuroscience
• Cellular Electrophysiology

Background:

• The Mauthner cell is a crucial component in the escape response of goldfish.
• Understanding its input conductance is vital for comprehending neuronal excitability.

Purpose of the Study:

• To analyze the leakage conductance of the goldfish Mauthner cell.
• To identify the ionic basis of the Mauthner cell's input conductance.

Main Methods:

• Single and double electrode voltage clamp techniques were employed.
• Analysis of voltage-dependent conductance and inactivation kinetics.

Main Results:

• Mauthner cell input conductance is maximal at resting potential (4.68 microS).
• Approximately 50% of conductance is voltage-dependent, inactivated by hyperpolarization.
• Evidence suggests a voltage-dependent K+ conductance, acting as an inward rectifier.

Conclusions:

• A significant portion of Mauthner cell input conductance is a voltage-dependent K+ conductance.
• This inward rectifier is maximally activated at resting potential, influencing neuronal excitability.
• The rectifier exhibits fast activation and inactivation kinetics.