MECHANORECEPTORS SENSITIVE TO FLOW AT THE GASTRODUODENAL JUNCTION OF THE CAT

Vagal afferent activity was recorded from the cervical vagus simultane ously with intraluminal pressure and flow rate at the proximal duodenu m, in cats anesthetized with pentobarbital sodium. Thirty-seven mechan oreceptors that adapted slowly to maintained pressure changes were fou nd to be sensitive to the flow of saline through the pylorus. The pass age of liquid was associated with an increase of pressure equal to one -tenth of that necessary to trigger a response of the receptors during the distension of a small balloon. The frequency of discharge was inc reased by the passage of liquid for positive back pressures less-than- or-equal-to 1.5 kPa but not when back pressure was negative. The relat ionship between the discharge of the receptor and the flow rate was co mplex and showed an hysteresis. We conclude that there exist slowly ad apting mechanoreceptors sensitive to distension of the duodenum that c an also sense the passage of liquid.