The enteric nervous system and immune system are integrated systems th
at play an important role in the regulation of gastrointestinal functi
ons. Recent studies suggest a bidirectional interaction between both s
ystems. The relationship is based on the synthesis and release of neur
opeptides from immune cells and the receptor-mediated alteration of ne
rvous and immune functions by neurotransmitters and inflammatory media
tors. The activity of the enteric nervous and immune system can be mod
ulated by the central nervous system. These psycho-neuro-immuno-intera
ctions are involved in gut inflammation, in functional bowel diseases
and in the physiological control of gastrointestinal functions.