Glutamate in the enteric nervous system.

Several lines of evidence indicate a role for glutamate in the regulation of gut motility and secretion; however, the receptor subtypes that mediate the effects of this amino acid are still incompletely understood. There has, however, been recent progress in pharmacological characterization of enteric glutamate receptor subtypes. In the past two years, investigators have demonstrated that in addition to ionotropic glutamate receptors, the enteric nervous system contains functional group I metabotropic glutamate receptors that appear to participate in enteric reflexes. This opens up an entirely new arena in which to study the roles of glutamate in gut function and presents potential new target sites for drug development.