Function ofthepylorus andpyloric antrum ingastric emptying

EDITORIALSYNOPSISThefunction ofthepylorus andthepyloric antruminthecontrol ofgastric emptying hasbeenstudied inan isolated ratstomach-duodenum preparation. Pressures inthe bodyandpyloric antrumandflowthrough theduodenum wererecorded using electronic transducers. Vigorous peristalsis andepisodic flow wereinduced byelectrical stimulation. Thepylorus isnormally open until itistransiently closed byan advancing peristaltic wave.Highpressures could develop intheantrumwhenitwas separated fromthebodybyanother peristaltic wave.Exclusion ofthepylorus hadverylittle effect on thepressuresdeveloped inbodyandantrum. Theclinical implications ofthese findings arediscussed. Inrecent years detailed studies ofpressures inthe body, antrumandduodenum havebeenmadeto investigate themechanics ofgastric emptying. Continuous measurement ofthechanging flowfrom thestomach totheduodenum isessential forcorrelating intragastric pressures withtheemptying of gastric contents butthisisextremely difficult in patients andconscious animals. Byusing a preparation invitro, however, pressure indifferent parts ofthestomach andtheflow produced canbestudied simultaneously. Experiments invitro havetheadditional advantage thatthemechanical andpharmacological control canbestudied uncomplicated by extrinsic factors. Muchofourrecent knowledge of thephysiology ofperistalsis hasinfact beenobtained fromsuchstudies (Bulbring, 1957-58; Bulbring and Crema, 1958). Recent investigations, suchasthose ofAtkinson, Edwards, HonourandRowlands (1957) andEdwards (1961), showthatthepylorus doesnotactasan independent sphincter controlling theexit ofgastric contents, andtheresults reported hereprovide further evidence thatthepylorus functions asan integral partoftheantrum. METHOD