P2X receptors in autonomic and sensory neurons

ATP-gated ion channels (P2X receptors) are ubiquitously present in autonomic and sensory neurons as well as in smooth muscle; they mediate fast excitatory synaptic transmission at sympathetic neuromuscular junctions, at some neuro-neuronal synapses and may be involved in the generation and transmission of primary afferent information. Five subtypes of native P2X receptors can be distinguished by their kinetics and their agonist and antagonist profile. Six distinct P2X receptors have been cloned; all are present in sensory neurons and most are present in autonomic neurons; homomeric or heteromeric forms of these cloned receptors reproduce the five phenotypes observed in native cells.