VAGOVAGAL REFLEX CONTROL OF DIGESTION - AFFERENT MODULATION BY NEURALAND ENDONEUROCRINE FACTORS

Vagovagal reflex control circuits in the dorsal vagal complex of the b rain stem provide overall coordination of gastric, small intestinal, a nd pancreatic digestive functions. The neural components forming these reflex circuits are under substantial descending neural control. By a djusting the excitability of the differing components of the reflex, s ignificant alterations in digestion control can be produced by the cen tral nervous system. Additionally, the dorsal vagal complex is situate d within a circumventricular region without a ''blood-brain barrier.'' As a result, vagovagal reflex circuitry is also exposed to humoral in fluences, which can profoundly alter digestive functions by acting dir ectly on brain stem neurons.