The role of visceral receptors in the mechanisms of neuroimmune interactions in mammalian small intestine

Exogenous administration of mast cell degranulation products into blood as well as their endogenous release induced by compound 48/80 or repeated egg albumin administration to sensitized rats proved to increase activity of mesenteric afferent nerve fibers in the small intestine. In addition, the primary contact with a foreign protein triggered a cascade of chemical processes mobilizing antioxidant systems and increasing nitric oxide production in the small intestinal tissues. Interleukin-1β or Escherichia coli lipopolysaccharide injections also had a long-term stimulating effect on intestinal receptors. Indometacin inhibited the effects induced by the bacterial endotoxin and interleukin-1β. The obtained data suggest that small intestinal interoceptors can monitor chemical environment and modulate body’s responses to foreign antigens. Interleukins-1β acts as a signal transmitter between immune cells and interoceptors, which is mediated by the production of secondary signal substances, in particular, prostaglandin E2 and histamine.