title: The distribution of P2X3 purine receptor subunits in the guinea pig enteric nervous system.
abstract: Adenosine 5'-triphosphate (ATP) excites 70-90% of enteric neurons through P2X type purine receptors, and is likely to be an enteric neurotransmitter. Recent studies indicate that the P2X2 subunit is expressed by specific subgroups of enteric neurons, and that there are enteric neurons that are responsive to ATP but lack this subunit. In the present work, we have investigated whether the P2X3 subunit is similarly localised to specific subgroups of neurons, and whether these are different from the P2X2 subunit-expressing neurons. The P2X3 subunit was localised by immunohistochemistry to nerve cells of the myenteric ganglia of the stomach, small and large intestines, and nerve cells of the submucosal ganglia in the small and large intestines of the guinea pig. All immunoreactivity was absorbed with the P2X3 receptor peptide against which the antiserum was raised. In myenteric ganglia of the ileum, P2X3 receptor immunoreactivity was in calretinin, enkephalin and nitric oxide synthase (NOS)-immunoreactive neurons. In submucosal ganglia, all calretinin-immunoreactive nerve cells were P2X3 receptor immunoreactive. In the submucosal ganglia of the ileum, 13 +/- 3% of neuropeptide Y (NPY)-immunoreactive neurons were also P2X3 receptor immunoreactive, whereas in the distal colon, almost all NPY-expressing nerve cells were P2X3 receptor immunoreactive. The localisation of the P2X3 subunit was largely distinct from that of the P2X2 subunit, although both subunits occur in some NOS neurons, where P2X2 and P2X3 subunits may form heteromeric receptors. Unlike the P2X2 subunit, the P2X3 subunit is not expressed in intrinsic sensory neurons in the ileum. It is concluded that the P2X3 receptor subunit is expressed in specific functional groups of neurons; the major types are excitatory and inhibitory muscle motor neurons, ascending interneurons and cholinergic secretomotor neurons.
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Poole
authors.forename: Patricia
authors.initials: P
authors.lastname: Castelucci
authors.forename: Heather L
authors.initials: HL
authors.lastname: Robbins
authors.forename: Roberto
authors.initials: R
authors.lastname: Chiocchetti
authors.forename: John B
authors.initials: JB
authors.lastname: Furness
mesh_terms: D000818:Animals; D064032:Calbindin 2; D017615:Enteric Nervous System / Q000378:metabolism*; D005260:Female; D005724:Ganglia / Q000166:cytology / Q000378:metabolism; D005753:Gastric Mucosa / Q000378:metabolism; D006168:Guinea Pigs; D007150:Immunohistochemistry / Q000379:methods; D007413:Intestinal Mucosa / Q000378:metabolism; D008297:Male; D009197:Myenteric Plexus / Q000166:cytology / Q000378:metabolism; D009478:Neuropeptide Y / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D018048:Receptors, Purinergic P2 / Q000378:metabolism*; D058477:Receptors, Purinergic P2X3; D064030:S100 Calcium Binding Protein G / Q000378:metabolism; D013004:Somatostatin / Q000378:metabolism; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism
chemical_list: D064032:Calbindin 2; D009478:Neuropeptide Y; D009687:Nuclear Proteins; D018048:Receptors, Purinergic P2; D058477:Receptors, Purinergic P2X3; D064030:S100 Calcium Binding Protein G; D014660:Vasoactive Intestinal Peptide; D013004:Somatostatin; D019001:Nitric Oxide Synthase