Neurophysiologic Mechanisms of Human Large Intestinal Motility

Bharucha, Adil E.; Brookes, Simon Jonathan

doi:10.1016/b978-0-12-382026-6.00036-1

Cited by 12 publications

(17 citation statements)

References 471 publications

(407 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A haustrum is defined here as a pocket-like transient structure created by circumferential muscle contractions. They are prominent in the human 23 and rabbit 3-taeniated colon 24 and we show here that they appear in the rat colon in the presence of neurotensin. We applied neurotensin in the organ bath or intraluminally.…”

Section: Introductionmentioning

confidence: 71%

“…Supplementary Videos 1 and 2, and Figures 2 and 6 show that there are several contractions traversing the colon at the same time, dividing the colon into segments or pockets; their boundaries created by the circumferential circular muscle contractions. In the human 23 and rabbit 24 colon, such segments or pockets are called haustra; the neurotensin induced motor pattern can thus be referred to as haustral boundary contractions. When the concentration of neurotensin reaches 10 nM or 100 nM, LDC activity is promoted and no induction of the slow propagating segmental contractions occurs.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Neurotensin Changes Propulsive Activity into a Segmental Motor Pattern in the Rat Colon

Chen

Yang

et al. 2016

J Neurogastroenterol Motil

View full text Add to dashboard Cite

Background/AimsNeurotensin is a gut-brain peptide with both inhibitory and excitatory actions on the colonic musculature; our objective was to understand the implications of this for motor patterns occurring in the intact colon of the rat. MethodsThe effects of neurotensin with concentrations ranging from 0.1-100 nM were studied in the intact rat colon in vitro, by investigating spatio-temporal maps created from video recordings of colonic motility before and after neurotensin. ResultsLow concentration of neurotensin (0.1-1 nM) inhibited propagating long distance contractions and rhythmic propagating motor complexes; in its place a slow propagating rhythmic segmental motor pattern developed. The neurotensin receptor 1 antagonist SR-48692 prevented the development of the segmental motor pattern. Higher concentrations of neurotensin (10 nM and 100 nM) were capable of restoring long distance contraction activity and inhibiting the segmental activity. The slow propagating segmental contraction showed a rhythmic contraction --relaxation cycle at the slow wave frequency originating from the interstitial cells of Cajal associated with the myenteric plexus pacemaker. High concentrations given without prior additions of low concentrations did not evoke the segmental motor pattern. These actions occurred when neurotensin was given in the bath solution or intraluminally. The segmental motor pattern evoked by neurotensin was inhibited by the neural conduction blocker lidocaine. ConclusionsNeurotensin (0.1-1 nM) inhibits the dominant propulsive motor patterns of the colon and a distinct motor pattern of rhythmic slow propagating segmental contractions develops. This motor pattern has the hallmarks of haustral boundary contractions. (J Neurogastroenterol Motil 2016;22:517-528)

show abstract

Section: Introductionmentioning

confidence: 71%

Section: Discussionmentioning

confidence: 99%

Neurotensin Changes Propulsive Activity into a Segmental Motor Pattern in the Rat Colon

Chen

Yang

et al. 2016

J Neurogastroenterol Motil

View full text Add to dashboard Cite

show abstract

“…Because of the haustral folds, the contractions appeared disorganized on a spatiotemporal map (Figs. [5][6][7][8], since the folds disappeared [the folds flapped open (Supplemental Movies S3-S5)] and appeared (folded) again. In addition to this, the apparent direction of propagation often switched, contributing to seemingly chaotic motor patterns.…”

Section: Haustral Boundary Contractionsmentioning

confidence: 96%

“…. caused by sustained contractions of the circular muscle" (11), that move slowly (5), or "the circular muscle layer is contracted intermittently to divide the colon into functional segments known as haustra" (2). Important insight into rabbit colon motility has been provided by Ehrlein (17), through his X-ray movies, and recently by Lentle et al (37) and Dinning et al (13) through spatiotemporal mapping.…”

mentioning

confidence: 99%

Haustral boundary contractions in the proximal 3-taeniated rabbit colon

Chen

Yang

et al. 2016

American Journal of Physiology-Gastrointestinal and Liver Physi

View full text Add to dashboard Cite

The rabbit proximal colon is similar in structure to the human colon. Our objective was to study interactions of different rhythmic motor patterns focusing on haustral boundary contractions, which create the haustra, using spatiotemporal mapping of video recordings. Haustral boundary contractions were seen as highly rhythmic circumferential ring contractions that propagated slowly across the proximal colon, preferentially but not exclusively in the anal direction, at ∼0.5 cycles per minute; they were abolished by nerve conduction blockers. When multiple haustral boundary contractions propagated in the opposite direction, they annihilated each other upon encounter. Ripples, myogenic propagating ring contractions at ∼9 cycles per min, induced folding and unfolding of haustral muscle folds, creating an anarchic appearance of contractile activity, with different patterns in the three intertaenial regions. Two features of ripple activity were prominent: frequent changes in propagation direction and the occurrence of dislocations showing a frequency gradient with the highest intrinsic frequency in the distal colon. The haustral boundary contractions showed an on/off/on/off pattern at the ripple frequency, and the contraction amplitude at any point of the colon showed waxing and waning. The haustral boundary contractions are therefore shaped by interaction of two pacemaker activities hypothesized to occur through phase-amplitude coupling of pacemaker activities from interstitial cells of Cajal of the myenteric plexus and of the submuscular plexus. Video evidence shows the unique role haustral folds play in shaping contractile activity within the haustra. Muscarinic agents not only enhance the force of contraction, they can eliminate one and at the same time induce another neurally dependent motor pattern.

show abstract

“…95,96 Postganglionic sympathetic neurons originate in the inferior mesenteric ganglion or pelvic plexus and travel to the IAS via lumbar colonic nerves, hypogastric nerves, or branches of the pelvic plexus. 7,97,98 Cutting the hypogastric nerve and/or lumbar colonic nerve as well as high spinal anesthesia reduces IAS contraction, whereas stimulation of sympathetic nerve trunks increases contraction. 4,[99][100][101][102][103][104][105][106] These data support an excitatory role for sympathetic nerves in the IAS.…”

Section: Excitatory Motor Innervationmentioning

confidence: 99%

Control of Motility in the Internal Anal Sphincter

Keef

Cobine

2019

J Neurogastroenterol Motil

View full text Add to dashboard Cite

The internal anal sphincter (IAS) plays an important role in the maintenance of fecal continence since it generates tone and is responsible for > 70% of resting anal pressure. During normal defecation the IAS relaxes. Historically, tone generation in gastrointestinal muscles was attributed to mechanisms arising directly from smooth muscle cells, ie, myogenic activity. However, slow waves are now known to play a fundamental role in regulating gastrointestinal motility and these electrical events are generated by the interstitial cells of Cajal. Recently, interstitial cells of Cajal, as well as slow waves, have also been identified in the IAS making them viable candidates for tone generation. In this review we discuss four different mechanisms that likely contribute to tone generation in the IAS. Three of these involve membrane potential, L-type Ca 2+ channels and electromechanical coupling (ie, summation of asynchronous phasic activity, partial tetanus, and window current), whereas the fourth involves the regulation of myofilament Ca 2+ sensitivity. Contractile activity in the IAS is also modulated by sympathetic motor neurons that significantly increase tone and anal pressure, as well as inhibitory motor neurons (particularly nitrergic and vasoactive intestinal peptidergic) that abolish contraction and assist with normal defecation. Alterations in IAS motility are associated with disorders such as fecal incontinence and anal fissures that significantly decrease the quality of life. Understanding in greater detail how tone is regulated in the IAS is important for developing more effective treatment strategies for these debilitating defecation disorders.

show abstract

Neurophysiologic Mechanisms of Human Large Intestinal Motility

Cited by 12 publications

References 471 publications

Neurotensin Changes Propulsive Activity into a Segmental Motor Pattern in the Rat Colon

Neurotensin Changes Propulsive Activity into a Segmental Motor Pattern in the Rat Colon

Haustral boundary contractions in the proximal 3-taeniated rabbit colon

Control of Motility in the Internal Anal Sphincter

Contact Info

Product

Resources

About