VAGAL CONTROL OF PYLORIC RESISTANCE

Pyloric resistance is probably a major factor regulating gastric empty ing of liquids, but its nervous control is unknown. The role of effere nt vagal pathways in pyloric resistance was evaluated in 13 anesthetiz ed pigs. Pyloric resistance was assessed by simultaneous recording of gastropyloroduodenal motility and transpyloric flow during gastric emp tying of saline. Cervical vagotomy suppressed all antral pressure even ts, increased the number of pressure events localized at the pylorus, and decreased the frequency of the flow pulses (P < 0.05), without aff ecting either pyloric resistance or the characteristics of flow pulses . Electrical stimulation of the cervical and the thoracic vagi both de creased pyloric resistance by about 60% and increased the stroke volum e of flow pulses (P < 0.05). The reduced pyloric resistance was mainly related to an alteration of the temporal relationship between flow pu lses and pyloric pressure events. These results indicate that vagal ef ferents could provide inhibitory inputs to pyloric resistance. A reduc tion in pyloric resistance contributes to the increased flow rate obse rved during vagal stimulation.