Selective KCNQ2/3 Potassium Channel Opener ICA-069673 Inhibits Excitability in Mouse Vagal Sensory Neurons

Area of Science:

• Neuroscience
• Pharmacology
• Physiology

Background:

• Heightened vagal sensory neuron excitability contributes to visceral pain and dysfunction in inflammatory diseases.
• KCNQ1-KCNQ5 genes encode K_V7 potassium channels that regulate neuronal excitability.
• K_V7.2-7.5 channels generate the M-current (I_M), which decreases neuronal excitability.

Purpose of the Study:

• To investigate if K_V7.2/7.3 channels are key regulators of vagal sensory neuron excitability.
• To evaluate the effects of the KCNQ2/3-selective activator, ICA-069673, on I_M and neuronal excitability.

Main Methods:

• Utilized patch clamp technique on mouse nodose neurons.
• Assessed the impact of ICA-069673 on M-current (I_M) density, activation, and deactivation.
• Measured effects on resting potential, input resistance, and action potential firing.

Main Results:

• ICA-069673 concentration-dependently enhanced I_M, accelerated activation, and delayed deactivation.
• ICA-069673 induced hyperpolarization, reduced input resistance, and increased the threshold for action potential firing.
• ICA-069673 limited action potential firing and had no effect when Kcnq2 and Kcnq3 were deleted.

Conclusions:

• Selective activation of KCNQ2/3-mediated M-channels effectively suppresses vagal sensory neuron excitability.
• ICA-069673 demonstrates potential as a therapeutic agent for visceral disorders characterized by nociceptor hyperexcitability.