Acid-sensitive ion channels and receptors.

Area of Science:

• Neuroscience
• Physiology
• Molecular Biology

Background:

• Acidosis, a condition linked to inflammation and ischemia, necessitates cellular acid sensing mechanisms.
• Primary afferent neurons possess specialized acid-sensing ion channels (ASICs) and transient receptor potential vanilloid-1 (TRPV1) channels.
• Various other acid-sensitive ion channels and G protein-coupled receptors contribute to pH surveillance.

Purpose of the Study:

• To review the diverse molecular mechanisms of acid sensing in primary afferent neurons.
• To explore the role of acid sensors in pain perception and physiological regulation.
• To evaluate acid-sensitive ion channels and receptors as therapeutic targets for chronic pain.

Main Methods:

• Literature review of studies on acid-sensitive ion channels and receptors.
• Analysis of the expression patterns of these sensors in sensory neurons.
• Examination of the functional roles in acid sensing, pain, and homeostasis.

Main Results:

• Multiple ion channels (ASICs, TRPV1, K(2P), TRPV4, TRPC4, TRPC5, TRPP2, P2X, K+, Ca2+, HCN, gap junctions, Cl-) and G protein-coupled receptors detect pH changes.
• These sensors are expressed in primary sensory neurons, with varying combinations and degrees.
• Evidence links acid sensors to acid-induced pain and the regulation of homeostasis.

Conclusions:

• The redundancy of pH sensing systems highlights the importance of acid-base balance for cellular and tissue homeostasis.
• Overactivity of acid sensors contributes to chronic pain conditions.
• Targeting acid-sensitive ion channels and receptors presents a promising strategy for novel analgesics, provided physiological functions can be distinguished from pathological roles.