Modulating fear extinction memory by manipulating SK potassium channels in the infralimbic cortex

Area of Science:

• Neuroscience
• Pharmacology
• Behavioral Science

Background:

• Fear extinction, a process crucial for treating anxiety disorders, is linked to increased infralimbic (IL) neuronal excitability.
• Small conductance calcium-activated potassium (SK) channels influence neuronal excitability and are implicated in learning and memory.

Purpose of the Study:

• To investigate the role of SK channels in the IL cortex in regulating fear extinction.
• To determine if pharmacological modulation of SK channels can influence IL neuronal excitability and fear extinction processes.

Main Methods:

• Whole-cell patch-clamp recordings in brain slices to assess the effect of apamin (SK channel blocker) on IL pyramidal neuron excitability.
• In vivo infusion of apamin and DCEBIO (SK channel activator) into the IL cortex of rats before fear extinction training.
• Behavioral assessment of conditioned freezing to measure fear extinction recall and acquisition.

Main Results:

• Apamin blockade of SK channels enhanced IL neuronal excitability.
• Infusion of apamin into the IL cortex impaired fear extinction recall the following day.
• Activation of SK channels with DCEBIO decreased IL neuronal excitability and impaired fear extinction recall, without affecting acquisition.

Conclusions:

• SK channels in the IL cortex play a significant role in regulating neuronal excitability and extinction-induced plasticity.
• Targeting SK channels pharmacologically presents a potential therapeutic strategy for enhancing fear extinction in anxiety disorders.