Colonic motor response to a meal in dogs

1989 ◽  
Vol 257 (5) ◽  
pp. G830-G835 ◽  
Author(s):  
S. K. Sarna ◽  
I. M. Lang
Keyword(s):  
Cycle Length ◽  
Contractile Activity ◽  
Total Duration ◽  
Early Period ◽  
Circular Muscle ◽  
Distal Colon ◽  
Postprandial Period ◽  
Colonic Motor ◽  
Colonic Motor Activity ◽  
The Mean

We investigated the effects of ingestion of a meal on colonic motor activity in six conscious dogs, each instrumented with seven strain-gauge transducers to record circular muscle contractions. A 1,300-kcal meal was given after a 4-h control recording. The post-prandial period of 8 h was subdivided into an early period lasting 2 h and a late period lasting 6 h. The ingestion of the meal did not disrupt the colonic migrating myoelectric complexes (CMMCs) but prolonged their cycle length in the early postprandial period. The cycle length was not different from the control during the late postprandial period. The mean and total duration of contractile activity per hour increased significantly during the early postprandial period in the distal colon but not in the proximal or the middle colon. During the late postprandial period the mean and total duration of contractile activity per hour increased significantly throughout the colon. Giant migrating contractions occurred rarely during the 8-h postprandial period. We conclude that different parts of the colon respond to the ingestion of a meal in different ways. The response also depends on whether the fresh digesta has reached the colon. The late postprandial response is likely to be due to the entry of fresh digesta into the colon.

Effects of physical exercise on colonic motor activity

1991 ◽  
Vol 260 (4) ◽  
pp. G646-G652 ◽  
Author(s):  
M. Dapoigny ◽  
S. K. Sarna
Keyword(s):  
Physical Exercise ◽  
Motor Activity ◽  
Contractile Activity ◽  
Total Duration ◽  
Distal Colon ◽  
Proximal Colon ◽  
Fed State ◽  
Fasted State ◽  
Colonic Motor ◽  
Colonic Motor Activity

We investigated the effect of physical exercise on colonic motor activity in the fasted and fed states in six conscious dogs. Each dog was implanted with nine strain gauge transducers: three on the proximal, three on the middle, and three on the distal colon. The dogs ran for 1 h on a treadmill at 5 km/h (slope 5%). In the fasted state, the dogs exercised during the 5th h of recording after an overnight fast, and in the fed state during the 1st, 3rd, and 5th postprandial hour. In the fasted state, exercise significantly decreased the frequency of colonic migrating motor complexes (MMCs) but had no effect on the total or the mean duration of contractile states in the proximal, middle, and distal colon. Postprandially, exercise disrupted colonic MMCs and replaced them with nonmigrating motor complexes in all three periods of exercise (1st, 3rd, and 6th h). Exercise also increased the total duration per hour of contractile activity throughout the colon during the 1st and 3rd h and only in the distal colon during the 6th h after the meal. The dogs never defecated during rest in the fasted or the fed state. Shortly after the start of exercise in the fasted and fed states, giant migrating contractions (GMCs) occurred, and they were followed by defecation. In approximately 40% of the experiments, another GMC originated in the proximal colon, approximately 10 min after the first defecation, and migrated caudad up to the middle colon. These GMCs were not associated with defecation but caused mass movements.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of fluid perfusion and cleansing on canine colonic motor activity

1992 ◽  
Vol 262 (1) ◽  
pp. G62-G68 ◽  
Author(s):  
S. K. Sarna
Keyword(s):  
Motor Activity ◽  
Motor Pattern ◽  
Total Duration ◽  
Distal Colon ◽  
Proximal Colon ◽  
Indwelling Catheter ◽  
Colonic Motor ◽  
Colonic Motor Activity ◽  
The Mean ◽  
Giant Migrating Contractions

We investigated the effect of absorbable and nonabsorbable fluid perfusion and cleansing on colonic motor activity in eight intact conscious dogs. Each dog was instrumented with an indwelling catheter in the proximal colon and seven strain gauge transducers on the entire colon. After an overnight fast, a control recording was made for 3 h, followed by 3 h of perfusion and 3 additional h of postperfusion recording. Next day, a 3-h recording was made when the colon was empty. The colon exhibited normal migrating and nonmigrating motor complexes in the control uncleansed state. The perfusion of absorbable electrolyte or nonabsorbable Colyte solution immediately disrupted the migrating motor complexes and replaced them with almost continuous but irregular contractions at all recording sites. Both solutions significantly prolonged the mean and total duration per hour of contractile states in the proximal, middle, and distal colon. The dogs began to leak fluid stools in squirts approximately 40-80 min after the start of perfusion. This type of incontinence was not associated with any specific type of motor activity. Infrequently, giant migrating contractions occurred during perfusion and caused explosive diarrhea. The migrating motor complexes remained disrupted during the 3-h postperfusion period. However, on the next day, the empty colon exhibited normal migrating motor complexes. The frequency of giant migrating contractions during perfusion and in the empty colon was significantly greater than that in the normal uncleansed colon. The total duration per hour of colonic motor activity in the empty colon was also greater than that in the normal uncleansed colon. We conclude that excessive fluid in the colon significantly alters its motor pattern.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of fractionated doses of ionizing radiation on colonic motor activity

1992 ◽  
Vol 263 (4) ◽  
pp. G518-G526 ◽  
Author(s):  
M. F. Otterson ◽  
S. K. Sarna ◽  
S. C. Leming ◽  
J. E. Moulder ◽  
J. G. Fink
Keyword(s):  
Motor Activity ◽  
Contractile Activity ◽  
Distal Colon ◽  
Colonic Motor ◽  
Colonic Motor Activity ◽  
The Mean ◽  
Motor Effects ◽  
Control State ◽  
Abdominal Irradiation ◽  
Giant Migrating Contractions

The colonic motor effects of fractionated irradiation were studied in five conscious dogs. Seven colonic and two ileal strain gauge transducers were implanted. After control recordings, an abdominal dose of 250 cGy was administered three times a week on alternate days for three successive weeks (total dose 2,250 cGy). Recordings were then continued for 3 wk after the completion of radiation. Colonic giant migrating contractions (GMCs) occurred at a frequency of 0.15 +/- 0.05 contractions/h in the control state. Only one of these contractions (8.3%) originated in the small bowel and propagated into the colon. Abdominal field irradiation significantly increased the incidence of colonic GMCs to 0.51 +/- 0.11 contractions/h (P < 0.05). Fifty-four percent of GMCs originated in the small intestine. GMCs during the radiation schedule were associated with explosive diarrhea on seven occasions. Irradiation did not alter the frequency of colonic migrating motor complexes, but the mean duration of contractile states decreased in the middle and distal colon. Diarrhea occurred as early as the second dose of radiation. Pathological changes in the colon were correlated with motor activity. Both small intestinal and colonic GMCs reverted to control frequencies after cessation of radiation exposure. Abdominal irradiation significantly altered the contractile activity of the colon. These changes are associated with abdominal cramping and diarrhea.

Cholinergic and nitrergic regulation of in vivo giant migrating contractions in rat colon

2002 ◽  
Vol 283 (3) ◽  
pp. G544-G552 ◽  
Author(s):  
Mona Li ◽  
Christopher P. Johnson ◽  
Mark B. Adams ◽  
Sushil K. Sarna
Keyword(s):  
Circular Muscle ◽  
Distal Colon ◽  
Rat Colon ◽  
Receptor Subtype ◽  
Colonic Motor ◽  
Calcitonin Gene ◽  
Colonic Motor Activity ◽  
Release Of Acetylcholine ◽  
Giant Migrating Contractions

The aim of this study was to characterize in vivo rat colonic motor activity in normal and inflamed states and determine its neural regulation. Circular muscle contractions were recorded by surgically implanted strain-gauge transducers. The rat colon exhibited predominantly giant migrating contractions (GMCs) whose frequency decreased distally. Only a small percentage of these GMCs propagated in the distal direction; the rest occurred randomly. Phasic contractions were present, but their amplitude was very small compared with that of GMCs. Inflammation induced by oral administration of dextran sodium sulfate suppressed the frequency of GMCs in the proximal and middle but not in the distal colon. Frequency of GMCs was suppressed by intraperitoneally administered atropine and 4-diphenylacetoxy- N-methyl-piperidine methiodide and was enhanced by N w-nitro-l-arginine methyl ester. Serotonin, tachykinin, and calcitonin gene-related peptide receptor or receptor subtype antagonists as well as guanethidine and suramin had no significant effect on the frequency of GMCs. Verapamil transiently suppressed the GMCs. In conclusion, unlike the canine and human colons, the rat colon exhibits frequent GMCs and their frequency is suppressed in inflammation. In vivo GMCs are stimulated by neural release of acetylcholine that acts on M3 receptors. Constitutive release of nitric oxide may partially suppress their frequency.

Colonic migrating and nonmigrating motor complexes in dogs

1984 ◽  
Vol 246 (4) ◽  
pp. G355-G360 ◽  
Author(s):  
S. K. Sarna ◽  
R. Condon ◽  
V. Cowles
Keyword(s):  
Motor Activity ◽  
Terminal Ileum ◽  
Strain Gauges ◽  
Myoelectric Activity ◽  
Quiescent State ◽  
Bipolar Electrodes ◽  
Colonic Motor ◽  
Colonic Motor Activity ◽  
The Mean ◽  
Small Intestinal

We report here the characteristics of a cyclic motor activity in the colon of conscious dogs and its relationship to small intestinal migrating motor complexes (MMCs). The colonic motor activity was recorded by four equispaced strain gauges and small intestinal myoelectric activity by four equispaced bipolar electrodes. The colonic motor activity was characterized by rhythmic bursts of contractions. The mean durations of bursts of contractions varied from 7.0 to 11.5 min at the four colonic recording sites. Those bursts of contractions which migrated over at least three recording sites were called colonic migrating motor complexes (CMMCs). All other patterns of bursts of contractions were called colonic nonmigrating motor complexes (CNMCs). A total of 160 CMMCs were recorded during a total recording period of 132 h; 151 CMMCs migrated caudad and 9 orad. The mean period of caudad migrating CMMCs was 53.3 +/- 5.4 (SE) min, and their mean migration time was 11.3 +/- 1.2 (SE) min. The onset of CMMCs was not temporally related to the onset of small intestinal migrating myoelectric complexes in the duodenum or their arrival in the terminal ileum. CMMCs did not have phases I to IV like those of small intestinal MMCs, but two consecutive CMMCs were separated by a quiescent state or by one or more randomly occurring bursts of contractions (CNMCs).

Local effect of substance P on colonic motor activity in different experimental states

1989 ◽  
Vol 256 (6) ◽  
pp. G997-G1004 ◽  
Author(s):  
J. Y. Hou ◽  
M. F. Otterson ◽  
S. K. Sarna
Keyword(s):  
Smooth Muscle ◽  
Substance P ◽  
Motor Activity ◽  
Short Duration ◽  
Motor Response ◽  
Cholinergic Neurons ◽  
Circular Muscle ◽  
Conscious State ◽  
Colonic Motor ◽  
Colonic Motor Activity

We studied the effects of close intra-arterial injections of substance P on colonic motor activity in the conscious state, during anesthesia, and during acute laparotomy. In the conscious state, with enteric nerves intact, substance P stimulated postsynaptic cholinergic neurons to induce a large amplitude and long duration contraction. This response was blocked by prior close intra-arterial injection of atropine and tetrodotoxin (TTX) but not hexamethonium. Hexamethonium and TTX given alone, close intra-arterially, induced a series of short-duration contractions. Prior close intra-arterial administration of hexamethonium significantly enhanced the colonic motor response to substance P. After blockade of nerve conduction by TTX, substance P induced a series of short-duration contractions with characteristics different from those when the nerves were functioning. Anesthesia alone had little effect on the colonic motor response to substance P, but laparotomy inhibited it significantly. Laparotomy similarly inhibited the contractile response to bethanechol. Gut handling had no further effect on this inhibition. We conclude that in the conscious state substance P acts preferentially on postsynaptic cholinergic neurons to contract colonic circular muscle. When the intrinsic nerves are blocked, substance P may act directly on the smooth muscle to induce circular muscle contractions with characteristics different from those induced when nerves are intact. Substance P also has a weak inhibitory motor effect by its action on presynaptic neurons that synapse on postganglionic intrinsic inhibitory neurons. Anesthetic doses of barbiturates have no major effects on the neuromuscular response to substance P, but laparotomy significantly inhibits the smooth muscle response and selectively blocks some neurons.

Anatomic modifications in the enteric nervous system of piebald mice and physiological consequences to colonic motor activity

2006 ◽  
Vol 290 (4) ◽  
pp. G710-G718 ◽  
Author(s):  
Seungil Ro ◽  
Sung Jin Hwang ◽  
Melodie Muto ◽  
William Keith Jewett ◽  
Nick J. Spencer
Keyword(s):  
Nervous System ◽  
Motor Activity ◽  
Large Bowel ◽  
Distal Colon ◽  
Histochemical Staining ◽  
Entire Colon ◽  
Colonic Motor ◽  
Severe Impairment ◽  
Colonic Motor Activity ◽  
Myenteric Ganglia

It has been assumed that in piebald lethal mice that develop megacolon, impaired colonic motor activity is restricted to the aganglionic distal colon. Peristaltic mechanical recordings, immunohistochemistry, and quantitative PCR were used to investigate whether regions of the colon, other than the aganglionic segment, may also show anatomical modifications and dysfunctional colonic motor activity. Contrary to expectations, colonic migrating motor complexes (MMCs) were absent along the whole colon of piebald lethal homozygote mice and severely impaired in heterozygote siblings. Aganglionosis was detected not only in the distal colon of piebald homozygote lethal mice (mean length: 20.4 ± 2.1 mm) but also surprisingly in their heterozygote siblings (mean length: 12.4 ± 1.1 mm). Unlike homozygote lethal mice, piebald heterozygotes showed no signs of megacolon. Interestingly, mRNA expression for PGP 9.5 was also dramatically reduced (by 71–99%) throughout the entire small and large bowel in both homozygote lethal and heterozygous littermates (by 67–87%). Histochemical staining confirmed a significant reduction in myenteric ganglia along the whole colon. In summary, the piebald mutation in homozygote lethal and heterozygote siblings is associated with dramatic reductions in myenteric ganglia throughout the entire colon and not limited to the distal colon as originally thought. Functionally, this results in an absence or severe impairment of colonic MMC activity in both piebald homozygote lethal and heterozygote siblings, respectively. The observation that piebald heterozygotes have an aganglionic distal colon (mean length: 12 mm) but live a normal murine life span without megacolon suggests that aganglionosis >12 mm and the complete absence of colonic MMCs may be required before any symptoms of megacolon arise.

Tonic and phasic motor activity in the proximal and distal colon of healthy humans

1998 ◽  
Vol 274 (3) ◽  
pp. G459-G464 ◽  
Author(s):  
Pauline Jouet ◽  
Benoît Coffin ◽  
Marc Lémann ◽  
Caroline Gorbatchef ◽  
Claire Franchisseur ◽  
...  
Keyword(s):  
Motor Activity ◽  
Distal Colon ◽  
Proximal Colon ◽  
Tonic Contraction ◽  
Fasting State ◽  
Liquid Meal ◽  
Healthy Humans ◽  
Colonic Motor ◽  
Postprandial Response ◽  
Colonic Motor Activity

In healthy humans, meals stimulate phasic and tonic motor activity in the unprepared distal colon. The response of the proximal colon remains unknown. In this study, we assessed the effect of a liquid meal on proximal and distal colonic motor activity. In 12 healthy volunteers, colonic tone and phasic motility were simultaneously recorded by using an electronic barostat and perfused catheters in the fasting state and in response to a 1,000-kcal meal. The meal significantly increased the phasic activity in the distal colon (230 ± 46% of the basal value; P = 0.02) but not in the proximal colon (138 ± 25% of the basal value; P = 0.2). The intrabag volume of the barostat was significantly more reduced in the distal than in the proximal colon (74 ± 11 vs. 50 ± 9% of the basal values, respectively; P = 0.04). We conclude that the postprandial response of the unprepared proximal colon is an immediate tonic contraction that is less pronounced than in the distal colon.

Vagal influence on colonic motor activity in conscious nonhuman primates

1992 ◽  
Vol 262 (2) ◽  
pp. G231-G236 ◽  
Author(s):  
M. Dapoigny ◽  
V. E. Cowles ◽  
Y. R. Zhu ◽  
R. E. Condon
Keyword(s):  
Motor Activity ◽  
Distal Colon ◽  
Adrenergic Blockade ◽  
Colonic Motor ◽  
Colonic Motor Activity ◽  
Adrenergic Blockers ◽  
Fast Control ◽  
Vagal Cooling ◽  
Vagal Influence

We investigated the role of the vagi in modulation of colonic motor activity in the fasted and fed states and determined the extent of vagal influence on colon motility in conscious monkeys. Monkeys were implanted with force transducers on the colon. A vagal cooling chamber was implanted supradiaphragmatically, and a vagal stimulating electrode was implanted just distal to the chamber. One week was allowed for recovery. After an overnight fast, control recordings were made for 1 h, and then the monkeys were either fed or remained fasting, with or without adrenergic blockade (propranolol and phentolamine). Then while recordings continued the vagi were cooled to their predetermined denervation temperature for 1 h. In a second set of experiments, adrenergic blockers were injected, and the vagi were stimulated during vagal cooling with or without atropine administration. In both the fasted and fed states, the contractile frequency was decreased during vagal cooling, with or without adrenergic blockade. With adrenergic blockade, however, the frequency of colon contractions was greater during cooling than during cooling without such blockade. Inhibition of colonic contractions during cooling decreased in magnitude from the proximal to the distal colon. Vagal efferent stimulation increased contractile frequency at all sites, but after atropine it decreased contractile frequency. We conclude that the vagi have either a direct or indirect influence on fasting and fed colonic motor activity throughout the colon, and that a nonadrenergic, noncholinergic inhibitory pathway is under vagal control.

scholarly journals Molecular and functional characterization of Kv7 K+ channel in murine gastrointestinal smooth muscles

2009 ◽  
Vol 297 (1) ◽  
pp. G107-G115 ◽  
Author(s):  
Thomas A. Jepps ◽  
Iain A. Greenwood ◽  
James D. Moffatt ◽  
Kenton M. Sanders ◽  
Susumu Ohya
Keyword(s):  
Contractile Activity ◽  
Functional Characterization ◽  
Smooth Muscles ◽  
Circular Muscle ◽  
Distal Colon ◽  
Muscle Layer ◽  
K Channel ◽  
Neuronal Membrane ◽  
Gi Tract ◽  
Membrane Excitability

Members of the Kv7 voltage-gated K+ channel family are important determinants of cardiac and neuronal membrane excitability. Recently, we and others have shown that Kv7 channels are also crucial regulators of smooth muscle activity. The aim of the present study was to assess the Kv7 expression in different parts of the murine gastrointestinal (GI) tract and to assess their functional roles by use of pharmacological agents. Of KCNQ/Kv7 members, both KCNQ4/Kv7.4 and KCNQ5/Kv7.5 genes and proteins were the most abundantly expressed Kv7 channels in smooth muscles throughout the GI tract. Immunohistochemical staining also revealed that Kv7.4 and Kv7.5 but not Kv7.1 were expressed in the circular muscle layer of the colon. In segments of distal colon circular muscle exhibiting spontaneous phasic contractions, the nonselective Kv7 blockers XE991 and linopirdine increased the integral of tension. Increases in the integral of tension were also observed under conditions of neuronal blockade. Similar effects, although less marked, were observed in the proximal colon. As expected, the Kv7.1-selective blocker chromanol 293B had no effect in either type of segment. These data show that Kv7.x especially Kv7.4 and Kv7.5 are expressed in different regions of the murine gastrointestinal tract and blockers of Kv7 channels augment inherent contractile activity. Drugs that selectively block Kv7.4/7.5 might be promising therapeutics for the treatment of motility disorders such as constipation associated with irritable bowel syndrome.

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