VAGAL CONTROL OF TRANSPYLORIC FLOW AND PYLORIC RESISTANCE

Vagal control of pyloric resistance was evaluated in anesthetised pigs by recording gastropyloroduodenal motility and transpyloric flow duri ng emptying of a liquid nonnutrient meal. Vagotomy did not modify pylo ric resistance or the characteristics of the flow pulses. Electrical s timulation of the distal stumps of cervical or thoracic vagus nerves d ecreased pyloric resistance and triggered flow pulses of large stroke volume. This was associated with increased fundic tone and pressurizat ion of the antrum. Phentolamine but not propranolol reduced the respon ses to vagal stimulation. These observations demonstrate that reduced pyloric resistance is one mechanism by which vagal activation promotes transpyloric flow.