Neurally mediated propagating discrete clustered contractions superimposed on myogenic ripples in ex vivo segments of human ileum.
Narrow muscle strips have been extensively used to study intestinal contractility. Larger specimens from laboratory animals have provided detailed understanding of mechanisms that underlie patterned intestinal motility. Despite progress in animal tissue, investigations of motor patterns in large, intact specimens of human gut ex vivo have been sparse. In this study, we tested whether neurally dependent motor patterns could be detected in isolated specimens of intact human ileum. Specimens (n = 14; 7-30 cm long) of terminal ileum were obtained with prior informed consent from patients undergoing colonic surgery for removal of carcinomas. Preparations were set up in an organ bath with an array of force transducers, a fiberoptic manometry catheter, and a video camera. Spontaneous and distension-evoked motor activity was recorded, and the effects of lidocaine, which inhibits neural activity, were studied. Myogenic contractions (ripples) occurred in all preparations (6.17 ± 0.36/min). They were of low amplitude and formed complex patterns by colliding and propagating in both directions along the specimen at anterograde velocities of 4.1 ± 0.3 mm/s and retrogradely at 4.9 ± 0.6 mm/s. In five specimens, larger amplitude clusters of contractions were seen (discrete clustered contractions), which propagated aborally at 1.05 ± 0.13 mm/s and orally at 1.07 ± 0.09 mm/s. These consisted of two to eight phasic contractions that aligned with ripples. These motor patterns were abolished by addition of lidocaine (0.3 mM). The ripples continued unchanged in the presence of this neural blocking agent. These results demonstrate that both myogenic and neurogenic motor patterns can be studied in isolated specimens of human small intestine.
Discipline of Human Physiology, Flinders University, Adelaide, South Australia, Australia;
Merel H
MH
Kuizenga
Discipline of Human Physiology, Flinders University, Adelaide, South Australia, Australia;
Tiong C
TC
Sia
Discipline of Human Physiology, Flinders University, Adelaide, South Australia, Australia;
Kelsi N
KN
Dodds
Discipline of Human Physiology, Flinders University, Adelaide, South Australia, Australia;
Lukasz
L
Wiklendt
Discipline of Computer Science, Engineering and Mathematics, Flinders University, Adelaide, South Australia, Australia;
John W
JW
Arkwright
Department of Surgical Pathology, Flinders Medical Centre, Bedford Park, South Australia, Australia;
A
A
Thomas
Discipline of Human Physiology, Flinders University, Adelaide, South Australia, Australia;
Simon J
SJ
Brookes
Discipline of Human Physiology, Flinders University, Adelaide, South Australia, Australia;
Nick J
NJ
Spencer
Discipline of Human Physiology, Flinders University, Adelaide, South Australia, Australia; Departments of Gastroenterology and Surgery, Flinders Medical Centre, Bedford Park, South Australia, Australia.
David A
DA
Wattchow
Discipline of Human Physiology, Flinders University, Adelaide, South Australia, Australia; Departments of Gastroenterology and Surgery, Flinders Medical Centre, Bedford Park, South Australia, Australia.
Phil G
PG
Dinning
Discipline of Human Physiology, Flinders University, Adelaide, South Australia, Australia; marcello.costa@flinders.edu.au.
Marcello
M
Costa
D000368:Aged; D000369:Aged, 80 and over; D000779:Anesthetics, Local / Q000494:pharmacology; D057785:Catheters; D017615:Enteric Nervous System / Q000187:drug effects / Q000502:physiology*; D005260:Female; D005336:Fiber Optic Technology; D005769:Gastrointestinal Motility / Q000187:drug effects; D006801:Humans; D007082:Ileum / Q000294:innervation*; D066298:In Vitro Techniques; D008012:Lidocaine / Q000494:pharmacology; D008297:Male; D008365:Manometry / Q000295:instrumentation; D008875:Middle Aged; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000294:innervation*; D011312:Pressure; D013997:Time Factors; D014160:Transducers, Pressure; D014741:Video Recording
D000779:Anesthetics, Local; D008012:Lidocaine
enteric nervous system; motor patterns; myogenic; neurogenic; small intestine