P2X receptors mediate ATP-induced primary nociceptive neurone activation

ATP-gated P2X ion-channel receptors are localised throughout the mammalian nervous system and have been identified on neurones which participate in co nduction of nociceptive information from the periphery to, and within, the CNS. This article briefly reviews recently published research describing th e role that ATP and P2X receptors may play in pain perception, highlighting the importance of the P2X, receptor in this process. The P2X, receptor sub unit is almost exclusively expressed on a subset of small and medium diamet er sensory neurones innervating cutaneous and visceral tissue. Activation o f P2X receptors present on the peripheral terminals of primary afferents re sults in neuronal depolarisation and, in conscious animals, leads to the ma nifestation of acute nociceptive behaviour. Recent animal studies have also shown that P2X, receptor expression is increased in sensory ganglia follow ing acute neuronal injury, hinting that similar plasticity in the expressio n of this receptor subtype could underlie the mechanisms involved in a rang e of conditions characterised by sensory hypersensitivity in man. It is app arent from the evidence available that functional antagonists at specific P 2X receptor subtypes could represent an important class of novel analgesic agents. (C) 2000 Elsevier Science B.V. All rights reserved.