Triggering of Major Brain Disorders by Protons and ATP:The Role of ASICs and P2X Receptors

Adenosine triphosphate(ATP)is well-known as a universal source of energy in living cells.Less known is that this molecule has a variety of important signaling func-tions:it activates a variety of specific metabotropic(P2Y)and ionotropic(P2X)receptors in neuronal and non-neu-ronal cell membranes.So,a wide variety of signaling func-tions well fits the ubiquitous presence of ATP in the tissues.Even more ubiquitous are protons.Apart from the unspe-cific interaction of protons with any protein,many physi-ological processes are affected by protons acting on specific ionotropic receptors--acid-sensing ion channels(ASICs).Both protons(acidification)and ATP are locally elevated in various pathological states.Using these fundamentally important molecules as agonists,ASICs and P2X receptors signal a variety of major brain pathologies.Here we briefly outline the physiological roles of ASICs and P2X receptors,focusing on the brain pathologies involving these receptors.