P2X2 purine receptor immunoreactivity of intraganglionic laminar endings in the mouse gastrointestinal tract

The distribution of P2X2 purine receptor subunit immunoreactivity has been investigated in the mouse gastrointestinal tract. Immunoreactivity occurred in intraganglionic laminar endings (IGLEs) associated with myenteric ganglia throughout the gastrointestinal tract. In the esophagus, IGLEs supplied every myenteric ganglion. The proportion of ganglia supplied decreased from 85% in the stomach to 10% in the ileum, and from 50% in the caecum to 15% in the distal colon. There was substantial loss of IGLEs from myenteric ganglia of all abdominal regions after bilateral subdiaphragmatic section of the vagus nerves. IGLEs in the esophagus consisted of dense clusters of punctate immunoreactive varicosities. In the stomach and duodenum they had prominent lamellar processes and irregular, but smaller, lamellae were found in other regions. Rare immunoreactive IGLEs occurred in the submucosa of the distal colon. P2X2 receptor immunoreactivity was on the surfaces and in the cytoplasm of a minority of nerve cells in myenteric ganglia. It is concluded that P2X2 purine receptor immunoreactivity is a feature of IGLEs in the mouse, and that P2X receptor agonists may modulate sensitivity of the IGLEs.