Acid-sensing ion channel

Acid-sensing ion channels (ASICs) are a family of ion channels that are activated by low extracellular pH. They belong to the DEG/ENaC superfamily of ion channels and are widely expressed in the nervous system, where they contribute to the sensation of pain, taste, and fear.

Structure

ASICs are composed of subunits, each of which has two transmembrane domains, a large extracellular loop, and short intracellular N and C termini. The channels are thought to assemble as trimers, with each subunit contributing to the formation of the ion pore.

Function

ASICs are activated by a decrease in extracellular pH, a condition that can occur during ischemia, inflammation, and in certain tumours. Upon activation, they allow the passage of Na+ ions into the cell, which can trigger a variety of cellular responses, including neuronal excitability, gene expression, and cell death.

Clinical significance

Due to their role in pain sensation and neuronal damage, ASICs are considered potential targets for the treatment of a variety of conditions, including neuropathic pain, ischemic brain injury, and certain types of cancer.

See also

• Ion channel
• DEG/ENaC
• Neuropathic pain
• Ischemia