Pharmacology and function of nicotinic acetylcholine and P2X receptors in the enteric nervous system.

There are many cell surface receptors expressed by neurones in the enteric nervous system (ENS). Ligand-gated ion channels are an important class of receptors expressed by enteric neurones. This review will focus on nicotinic acetylcholine receptors (nAChRs) and P2X receptors for ATP, as these receptors contribute to fast synaptic transmission in identified pathways in the ENS. There are multiple subunit proteins that compose nAChRs and P2X receptors in the nervous system. Functional and pharmacological studies indicate that the predominant class of nAChR mediating fast synaptic transmission in enteric neurones is composed of alpha3 and beta4 subunits. P2X receptors mediating fast synaptic excitation are predominately P2X2 homomeric receptors.