ABSTRACT
The digestive system is controlled by a complex net of feedback mechanisms, by which the gut is able to sense and react to a variety of stimuli. Feedback control of gut function is operated via reflex pathways distributed within the enteric nervous system and both the sympathetic and parasympathetic nervous systems. This organization allows the digestive system a high degree of versatility and adaptation to a wide range of situations. Nevertheless, under some circumstances gut stimuli may activate perception pathways and induce conscious sensations. The peripheral neurons of this viscerosensory system are located in the posterior root ganglia with a visceral projection along sympathetic-splanchnic pathways and central projection into the spinal cord (1-3). Hence, while the operation of the digestive system is assured by a complex wiring of reflex arcs, there is also a sensory alarm system that may be activated to signal dysfunction, translated into symptoms, that is, abnormal conscious sensations. To some extent, the sensory system may be also involved in pleasant gut sensations, that may contribute to gastrointestinal comfort and well-being, but this aspect is still virtually unexplored.
