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Mañé N, Jimenez M. Interplay between myogenic pacemakers and enteric neurons determine distinct motor patterns in the rat colon. Neurogastroenterol Motil 2014; 26:1508-12. [PMID: 25088991 DOI: 10.1111/nmo.12393] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 06/13/2014] [Indexed: 01/14/2023]
Abstract
Waxing and waning of slow waves amplitude has been recently associated with a segmentation motor pattern in the murine small intestine. The 'wax and wane' phenomenon in this area of the gastrointestinal tract seems to be the result of modulation of slow waves by a second pacemaker of a lower frequency displayed by the interstitial cells of Cajal near the deep muscular plexus (ICC-DMP). In the rat colon, smooth muscle cyclic depolarizations causing low-frequency (LF) contractions (0.9 ± 0.1 cpm) occur together with slow wave activity associated to high-frequency (HF) contractions (14 ± 0.3 cpm; ripples). In the present manuscript, we demonstrate the presence of 'wax and wane' in rat colonic slow waves. Depolarization from the 'wax' to the 'wane' was 7.6 ± 1.2 mV, i.e., smooth muscle cells went from a resting membrane potential (RMP) of -50.0 mV to a RMP of -42.4 mV. The amplitude of the slow wave decreased from 14.0 ± 2.2 mV to 3.4 ± 0.7 mV. The wax and wane phenomenon occurred at 0.9 ± 0.1 cpm, coinciding with the frequency of cyclic depolarizations. Therefore, we hypothesized that the 'wax and wane' of slow waves in the rat colon could be the result of their interaction with the LF pacemaker. We describe three different myogenic motor patterns that depend on the level of smooth muscle and ICC excitation: (i) LF propulsive contractions, (ii) regular slow waves causing ripples, and (iii) a wax and wane pattern that may lead to segmentation. Different intra- and extra-luminal inputs probably determine the dominating motor pattern in each area through the enteric nervous system.
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Affiliation(s)
- N Mañé
- Department of Cell Biology, Physiology and Immunology and Neuroscience Institute, Universitat Autònoma de Barcelona, Barcelona, Spain
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DINNING PG, WIKLENDT L, MASLEN L, GIBBINS I, PATTON V, ARKWRIGHT JW, LUBOWSKI DZ, O'GRADY G, BAMPTON PA, BROOKES SJ, COSTA M. Quantification of in vivo colonic motor patterns in healthy humans before and after a meal revealed by high-resolution fiber-optic manometry. Neurogastroenterol Motil 2014; 26:1443-57. [PMID: 25131177 PMCID: PMC4438670 DOI: 10.1111/nmo.12408] [Citation(s) in RCA: 140] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 07/04/2014] [Indexed: 02/06/2023]
Abstract
BACKGROUND Until recently, investigations of the normal patterns of motility of the healthy human colon have been limited by the resolution of in vivo recording techniques. METHODS We have used a new, high-resolution fiber-optic manometry system (72 sensors at 1-cm intervals) to record motor activity from colon in 10 healthy human subjects. KEY RESULTS In the fasted colon, on the basis of rate and extent of propagation, four types of propagating motor pattern could be identified: (i) cyclic motor patterns (at 2-6/min); (ii) short single motor patterns; (iii) long single motor patterns; and (iv) occasional retrograde, slow motor patterns. For the most part, the cyclic and short single motor patterns propagated in a retrograde direction. Following a 700 kCal meal, a fifth motor pattern appeared; high-amplitude propagating sequences (HAPS) and there was large increase in retrograde cyclic motor patterns (5.6 ± 5.4/2 h vs 34.7 + 19.8/2 h; p < 0.001). The duration and amplitude of individual pressure events were significantly correlated. Discriminant and multivariate analysis of duration, gradient, and amplitude of the pressure events that made up propagating motor patterns distinguished clearly two types of pressure events: those belonging to HAPS and those belonging to all other propagating motor patterns. CONCLUSIONS & INFERENCES This work provides the first comprehensive description of colonic motor patterns recorded by high-resolution manometry and demonstrates an abundance of retrograde propagating motor patterns. The propagating motor patterns appear to be generated by two independent sources, potentially indicating their neurogenic or myogenic origin.
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Affiliation(s)
- P. G. DINNING
- Departments of Gastroenterology and Surgery, Flinders Medical Centre, Bedford Park, South Australia, Australia, Disciplines of Human Physiology, Flinders University, Bedford Park, South Australia, Australia, St. George Hospital Clinical School, Faculty of Medicine, University of New South Wales, Kogarah, New South Wales, Australia
| | - L. WIKLENDT
- Disciplines of Human Physiology, Flinders University, Bedford Park, South Australia, Australia
| | - L. MASLEN
- Departments of Gastroenterology and Surgery, Flinders Medical Centre, Bedford Park, South Australia, Australia
| | - I. GIBBINS
- Anatomy and Histology, Flinders University, Bedford Park, South Australia, Australia
| | - V. PATTON
- St. George Hospital Clinical School, Faculty of Medicine, University of New South Wales, Kogarah, New South Wales, Australia, Department of Anorectal Physiology, St George Hospital, Kogarah, New South Wales, Australia
| | - J. W. ARKWRIGHT
- Computer Science, Engineering and Mathematics, Flinders University, Bedford Park, South Australia, Australia
| | - D. Z. LUBOWSKI
- Disciplines of Human Physiology, Flinders University, Bedford Park, South Australia, Australia
| | - G. O'GRADY
- Department of Surgery, University of Auckland, Auckland, New Zealand
| | - P. A. BAMPTON
- Departments of Gastroenterology and Surgery, Flinders Medical Centre, Bedford Park, South Australia, Australia
| | - S. J. BROOKES
- Disciplines of Human Physiology, Flinders University, Bedford Park, South Australia, Australia
| | - M. COSTA
- Disciplines of Human Physiology, Flinders University, Bedford Park, South Australia, Australia
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Challis RE, Richards SR, Wingate DL. Signal preprocessing system for the small intestinal electromyogram. Med Biol Eng Comput 1989; 27:117-24. [PMID: 2601429 DOI: 10.1007/bf02446219] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The intestinal EMG obtained from chronically implanted electrodes in canine preparations provides for the evaluation of intestinal motor activity and its control. The basic electrical rhythm (BER) and spike components on the EMG signal provide evidence of control activity and a measure of contraction intensity, respectively. A hardware system is presented in which these two components are separated by filters and the contraction spikes counted in fixed epochs to yield a contraction spike per unit time record against time. The signal is also available in parallel binary form at the end of each epoch, together with a data-ready signal for direct acquisition by computer. Tests of system performance and operating protocols are given. The preprocessor is used as a fast front end to a digital signal processing system specifically built for intestinal EMG analyses.
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Abstract
Human colonic motility is governed by control mechanisms involving the electrical activity of the smooth muscle cell membranes, the intrinsic and extrinsic nervous activity, and hormonal action. The structural bases for neural and myogenic control have not been demonstrated. However, gap junctions are lacking between muscle cells, and nerves are not close to smooth muscle cells. The myogenic control, as observed in vitro, is described and compared with results obtained from different in vivo techniques. In vitro and in vivo measurements are critically evaluated, and a reconciliation between them attempted. No appropriate animal model is available to help resolve different findings and interpretations. Neural control of colon motility is exerted probably through modulation of myogenic activity as well as directly. The activities of extrinsic nerves, intrinsic motor nerves and afferent nerves are integrated within the colon, at prevertebral ganglia and in the spinal cord in animals, but similar data are not available for the human. There is a lack of studies directly relating transit to motility and conventional beliefs need reexamination.
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Abstract
1. Extracellular and intracellular recordings were made of the electrical activity of isolated strips of human colonic smooth muscle, cut from sixty surgical specimens. 2. Strips of taenia were spontaneously active. The myogenic activity consisted in half the strips of intermittent periods of regular spike activity (frequency 22 +/- 5 (S.D.) c/min) accompanied by tetanic contractions; in the other half of the strips activity was continuous. In half the specimens, slow potentials were recorded between periods of spike activity. Slow potentials were not accompanied by contractions. 3. Spikes in taenia were abolished by verapamil. Spikes disappeared in low Ca and low Na solutions, but in low Na solution spikes could be stimulated by 15 mM-KCl. 4. ACh and physotigmine produced tetanic contractions in taenia. 5. Circular muscle was not spontaneously active within 1 h of incubation in the water bath, possibly due to inhibition by prostaglandins. 6. Circular muscle responded to ACh with irregular bursts of spikes associated with discrete contractions. Similar activity was seen after inhibition of prostaglandin synthesis with indomethacin. After treatment with tetrodotoxin, ACh produced regular spikes and tetanic contractions in circular muscle. 7. The possible relationships of these results to the myoelectrical activity of the human colon in vivo are discussed.
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De Groat WC, Krier J. The sacral parasympathetic reflex pathway regulating colonic motility and defaecation in the cat. J Physiol 1978; 276:481-500. [PMID: 650474 PMCID: PMC1282439 DOI: 10.1113/jphysiol.1978.sp012248] [Citation(s) in RCA: 86] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
1. The sacral parasympathetic outflow to the large intestine of the cat was studied by monitoring simultaneously intestinal motility and the efferent firing in postganglionic fibres on the serosal surface of the mid-distal colon. 2. Increases in efferent firing were noted during the occurrence of spontaneous propulsive activity (tonic pressure waves) or segmental contractions (slow rhythmic pressure waves). The neural discharge was not altered by transection of the lumbar sympathetic innervation to the colon but was blocked by interruption of the sacral parasympathetic outflow. 3. Electrical stimulation of pelvic nerve afferents arising in the colon or distension of the colon or rectum evoked reflex increases in efferent firing and sustained propulsive contractions that were associated with defaecation. Both responses were abolished by transection of the pelvic nerves or sacral dorsal roots. 4. Electrical stimulation of colonic afferent fibres also evoked synchronous reflex discharges in colonic efferents at latencies ranging from 180 to 300 msec. The discharges were enhanced during propulsive contractions, abolished by transection of the pelvic nerves but not altered by transection of the lumbar sympathetic nerves. 5. Sacral reflexes were present in cats with intact spinal cord and in chronic spinal animals (transection at T10-T12). The reflexes recovered within minutes to several hours after acute transection of the spinal cord. 6. Electrophysiological measurements indicated that the sacral reflexes to the large intestine were mediated by non-myelinated afferent and preganglionic efferent fibres. The central delay for the reflex was estimated to be 45-60 msec. 7. It is concluded that the sacral parasympathetic reflexes to the large intestine are mediated via a spinal pathway and have an essential role in the initiation of propulsive activity during defaecation.
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