The Interdigestive Housekeeper of the Gastrointestinal Tract

THE INTERDIGESTIVE HOUSEKEEPER OF THE GASTROINTESTINAL TRACT* CHARLES F. CODEÎ That the "housekeeper" migrates down the gastrointestinal tract was discovered byJoseph H. Szurszewski while we were working together at die Mayo Clinic, Rochester, Minnesota [I]. For years I had wanted to record, all at one time, the motor action of the entire tract in happy, healthy, conscious, well-adjusted dogs! Tiny electrical detectors sewn to the outer muscle coats at intervals over the length of the tract provided tiiis opportunity. No one before had ever had enough recording units scattered over the bowel and working simultaneously. When Joe's dogs were fasted for 18 hours or more, he reported they were showing a repetitive pattern. His observations were on rolls of 100 feet or more—6-8 or more hours of continuous recording. We taped diem to the wall around our seminar-lecture theatre so we could review 8 hours ofrecording in continuity at a glance. "Look, Dr. Code. Here is a period of intense maximal action potential activity starting in the duodenum. After a few minutes it takes off and passes as a band, slowly down to die terminal ileum!" (fig. 1). "Joe, you have it—this burst of basic rhydim actually migrates. Terrific!" The possibility had never occurred to me, nor as far as I know, to anyone else. It was a discovery. We were bodi excited. Joe commented diat die periods of powerful activity were like storm fronts sweeping across Minnesota. They have been known as "fronts" or "activity fronts" ever since [1,2]. It has been known for years that the stomach and small bowel show periods of intense rhydimic motor contractions during fasting. BoIdyreff , when he was Pavlov's pupil in Saint Petersburg at die turn of the century, had recorded periods of powerful contractions in the stomach and small bowel of fasted dogs but he never knew drey passed from one *The fifth Walter Palmer Lecture, University of Chicago, November 16, 1977. tProfessor of physiology and medicine, University ofCalifornia, and associate director, Center for Ulcer Research and Education, V. A. Wadsworth Hospital Center, Los Angeles 90083. Research supported by NIH grants AM 18618, AM 17328, and the Mayo Foundation .,© 1979 by The University of Chicago. 0031-5982/79/2222-O003$01.O0 Perspectives in Biology andMediane ¦ Winter 1979 · Part2 | S49 Pylorut J I Electrode 16 Coudai [Cl 65 152 236 27S Colon oa] 320 326 Minutes After Onttt of Phase m In Stomach and Duodenum Onsst7 256997 I I 132 ^¦J^^^I^JJj^J^J^JfjJ^'pJp*J>«J/«J^.**Jf*J»~JjmJf.^¿^«f^^J***JpjO-J^. o2 jftitytytytytyifl^ffpHWimmmm. *?·^?.?^ß^^ j, .í^flftSflt#'ttj1í»* *MW^i^»ß 2 >*+W^^**fVcV·*eMJWM»*AdV+*"M·* 1 tt , x,m x ^HV*ArY*H*«VVWr/\Vln^VWW\JW4MA^^,^^Mfc^ft^V"Ww -|^vH/v •îYfrVtpi''»v·30«e Fig. 1 .—Segments of a continuous electrical recording from the stomach and small bowel of a fasted, conscious, healthy dog. Minutes after onset of the activity front in the duodenum is shown above the strip of record. Distance of recording electrodes from the pylorus is indicated in cm. Caudad migration of the band of intense action potential activity—the activity front—from the duodenum (D) over thejejunum (J) and ileum (I) is shown. The action potentials when maximal appear as dark segments in the recording [9, p. 294]. site to another [3]. Neither did Donald Douglas when in 1935 he showed me his beautiful records showing periodic bursts of powerful rhythmic contractions in the small bowel of fasted, conscious, well-trained dogs. He was working dien at Mayo widi Dr. F. C. Mann [4]. Neither did Bill Foulk nor I when we saw the same activity in human beings in the early 1950s [5]. Others missed it, too [6]—inexplicable! This interdigestive motor and electrical activity follows a standard, stereotyped pattern. It has been observed in all of the mammals so far tested which experience interdigestive periods—periods between digestive episodes. The full pattern does not occur in ruminants whose stomachs are normally never empty [6, 7]. When, in odier species, die stomach and small bowel are finished processing all die eaten food, do diey simply settle back for a rest...