A Malcolm1, M Camilleri. 1. Gastroenterology Research Unit, Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905, USA.
Abstract
OBJECTIVE: The rectoanal inhibitory reflex facilitates defecation by relaxation of the internal anal sphincter during rectal distention by gas or stool. Defecation is sometimes preceded by high-amplitude propagated contractions (HAPCs). Our objective was to seek evidence for motor coordination between human colonic and anal sphincter functions. METHODS: As part of a study of alpha2 modulation of colonic and anal motor functions in 32 healthy volunteers, we studied the relationship between high HAPCs and anal sphincter pressure with colonic manometry, barostat, and a Dent sleeve in the anal canal. RESULTS: Twenty-two HAPCs were observed; in 19/22 HAPCs there was optimal positioning of the Dent sleeve to assess the anal sphincter. Eighteen of 19 HAPCs occurred postprandially; 14 HAPCs occurred after administration of yohimbine, three after clonidine, and one before any drug administration. Seven followed experimental balloon distention. Anal sphincter relaxation occurred (14 +/- 4 s) before the recorded onset of HAPC in the descending colon and 88 +/- 7 s before the arrival of the HAPC in the rectum. After or during the HAPCs, anal sphincter pressure decreased by 40 +/- 4% and increased by 56 +/- 8% in the postrelaxation phase. CONCLUSIONS: The close temporal association between anal sphincter relaxation and onset of HAPC in the descending colon suggests a coloanal reflex that may facilitate defecation during mass movements independently of the rectoanal inhibitory reflex.
OBJECTIVE: The rectoanal inhibitory reflex facilitates defecation by relaxation of the internal anal sphincter during rectal distention by gas or stool. Defecation is sometimes preceded by high-amplitude propagated contractions (HAPCs). Our objective was to seek evidence for motor coordination between humancolonic and anal sphincter functions. METHODS: As part of a study of alpha2 modulation of colonic and anal motor functions in 32 healthy volunteers, we studied the relationship between high HAPCs and anal sphincter pressure with colonic manometry, barostat, and a Dent sleeve in the anal canal. RESULTS: Twenty-two HAPCs were observed; in 19/22 HAPCs there was optimal positioning of the Dent sleeve to assess the anal sphincter. Eighteen of 19 HAPCs occurred postprandially; 14 HAPCs occurred after administration of yohimbine, three after clonidine, and one before any drug administration. Seven followed experimental balloon distention. Anal sphincter relaxation occurred (14 +/- 4 s) before the recorded onset of HAPC in the descending colon and 88 +/- 7 s before the arrival of the HAPC in the rectum. After or during the HAPCs, anal sphincter pressure decreased by 40 +/- 4% and increased by 56 +/- 8% in the postrelaxation phase. CONCLUSIONS: The close temporal association between anal sphincter relaxation and onset of HAPC in the descending colon suggests a coloanal reflex that may facilitate defecation during mass movements independently of the rectoanal inhibitory reflex.
Authors: A E Bharucha; T Skaar; C N Andrews; M Camilleri; S Philips; B Seide; D Burton; K Baxter; A R Zinsmeister Journal: Neurogastroenterol Motil Date: 2008-04-16 Impact factor: 3.598
Authors: Satish Sc Rao; Adil E Bharucha; Giuseppe Chiarioni; Richelle Felt-Bersma; Charles Knowles; Allison Malcolm; Arnold Wald Journal: Gastroenterology Date: 2016-03-25 Impact factor: 22.682
Authors: Seth Sweetser; Irene A Busciglio; Michael Camilleri; Adil E Bharucha; Lawrence A Szarka; Athanasios Papathanasopoulos; Duane D Burton; Deborah J Eckert; Alan R Zinsmeister Journal: Am J Physiol Gastrointest Liver Physiol Date: 2008-11-25 Impact factor: 4.052