Receptors and Transmission in the Brain-Gut Axis - II. Excitatory amino acid receptors in the brain-gut axis

In the last decade, there has been a dramatic increase in academic and phar maceutical interest in central integration of vago-vagal reflexes controlli ng the gastrointestinal tract. Associated with this, there have been substa ntial efforts to determine the receptor-mediated events in the dorsal vagal complex that underlie the physiological responses to distension or variati ons in the composition of the gut contents. Strong evidence supports the id ea that glutamate is a transmitter in afferent vagal fibers conveying infor mation from the gut to the brain, and the implications of this are discusse d in this themes article. Furthermore, both ionotropic and metabotropic glu tamate receptors mediate pre- and postsynaptic control of glutamate transmi ssion related to several reflexes, including swallowing motor pattern gener ation, gastric accommodation, and emesis. The emphasis of this themes artic le is on the potential therapeutic benefits afforded by modulation of these receptors at the site of the dorsal vagal complex.