scholarly journals Dextran Sodium Sulphate (DSS)-Induced Colitis Alters the Expression of Neurotrophins in Smooth Muscle Cells of Rat Colon

2017 ◽  
pp. 1009-1020 ◽  
Author(s):  
M. AL-QUDAH ◽  
D. A. SHAMMALA ◽  
A. AL-DWAIRI ◽  
O. AL-SHBOUL ◽  
A. G. MUSTAFA

Neurotrophins are present in the gastrointestinal tract where they participate in the survival and growth of enteric neurons, augmentation of enteric circuits, elevation of colonic myoelectrical activity and also in different aspects of colitis. Previous studies largely focused on the role of neural and mucosal neurotrophins in gut inflammation. The expression of neurotrophins in colonic smooth muscle cells (SMCs) and the interactions of this potential source with colitis has not been studied in the gut. The expression of NGF, BDNF, NT-3 and NT-4 in SMCs from longitudinal and circular muscle layers of rat colon from normal and dextran sodium sulphate (DSS)-induced colitis rats was measured by ELISA. NGF, BDNF, NT-3 and NT-4 are differentially expressed in both longitudinal and circular SMCs, where the expressions of BDNF and NT-4 proteins were greater in SMCs from the longitudinal muscle layer than from the circular muscle layer, while NGF protein expression was greater in circular SMCs and NT-3 expression was equal in cells from both muscle layers. Induction of colitis with DSS significantly alters neurotrophins expression pattern in colonic SMCs. NGF levels upregulated in circular SMCs. BDNF level was increased in DSS-induced colitis in longitudinal SMCs. NGF, NT-3 and NT-4 levels were downregulated in longitudinal SMCs of DSS-induced colitis rats' colon. Disturbances of neurotrophins expression in SMCs resulted from colitis might account for the structural and functional changes in inflammatory bowel disease (IBD) such as loss of innervation and characteristic hypercontractility of longitudinal muscle in IBD.

2001 ◽  
Vol 281 (1) ◽  
pp. G275-G282 ◽  
Author(s):  
Asensio Gonzalez ◽  
Sushil K. Sarna

The rat middle colon spontaneously generates regularly occurring giant contractions (GCs) in vitro. We investigated the neurohumoral and intracellular regulation of these contractions in a standard muscle bath. cGMP content was measured in strips and single smooth muscle cells. The circular muscle strips generated spontaneous GCs. Their amplitude and frequency were significantly increased by tetrodotoxin (TTX), ω-conotoxin, N ω-nitro-l-arginine (l-NNA), and the dopamine D1 receptor antagonist Sch-23390. The GCs were unaffected by hexamethonium, atropine, and antagonists of serotonergic (5-HT1–4), histaminergic (H1–2), and tachykininergic (NK1–2) receptors but enhanced by NK3receptor antagonism. The guanylate cyclase inhibitor 1H-[1,2,4]oxidiazolo[4,3-a]quinoxalin-1-one (ODQ) also enhanced GCs to the same extent as TTX and l-NNA, and each of the three agents prevented the effects of the others. GCs were abolished by electrical field stimulation, S-nitroso- N-acetyl-penicillamine, and 8-bromo-cGMP. BAY-K-8644 and apamin enhanced the GCs, but they were abolished by D-600. Basal cGMP content in strips was decreased by TTX,l-NNA, or ODQ, but these treatments had no effect on cGMP content of enzymatically dissociated single smooth muscle cells. We conclude that spontaneous contractions in the rat colonic muscle strips are not generated by cholinergic, serotonergic, or histaminergic input. Constitutive release of nitric oxide from enteric neurons sustains cGMP synthesis in the colonic smooth muscle to suppress spontaneous in vitro GCs.


1995 ◽  
Vol 268 (6) ◽  
pp. C1492-C1502 ◽  
Author(s):  
L. Farraway ◽  
A. K. Ball ◽  
J. D. Huizinga

Intercellular communication within the musculature of the canine colon was studied by examining the results of neurobiotin diffusion after injection of the tracer into smooth muscle cells at different locations within the muscle layer. Circular muscle at the submucosal surface, circular muscle adjacent to the myenteric plexus, and longitudinal muscle demonstrated different degrees of time-dependent tracer spread. At the submucosal surface, tracer spread was rapid, extensive, and unimpeded by connective tissue septa. At the myenteric side, tracer spread was also extensive but was much slower and confined to bundles of cells bordered by septa. In contrast to previous studies that suggest an absence of gap junctions at the myenteric side of the circular muscle, the neurobiotin spread indicates full metabolic coupling of all circular smooth muscle cells. Furthermore, in contrast to the belief that longitudinal muscle is completely devoid of gap junctions, tracer spread occurred between cells in this layer, although neurobiotin diffusion was very limited, nonuniform, and slow. In each area of the musculature studied, tracer spread was inhibited by octanol. When very long injection and wait times were implemented at the submucosal surface of the circular muscle, neurobiotin was observed to cross septa through the network of interstitial cells of Cajal, indicating that it is this network that provides communication between lamellae.


2001 ◽  
Vol 149 (23) ◽  
pp. 707-711 ◽  
Author(s):  
N. P. H. Hudson ◽  
I. G. Mayhew ◽  
G. T. Pearson

Intracellular microelectrode recordings were made from smooth muscle cells in cross-sectional preparations of equine ileum, superfused in vitro. Membrane potential oscillations and spike potentials were recorded in all preparations, but recordings were made more readily from cells in the longitudinal muscle layer than from cells in the circular layer. The mean (se) resting membrane potential (RMP) of smooth muscle cells in the longitudinal muscle layer was -51.9 (1.2) mV, and the membrane potential oscillations in this layer had a mean amplitude of 4.8 (0.4) mV, a frequency of 9.0 (0.1) cycles per minute and a duration of 5.8 (0.2) seconds. The membrane potential oscillations were preserved in the presence of tetrodotoxin. A waxing and waning pattern of membrane potential oscillation activity was observed. Nifedipine abolished the spiking contractile activity of the smooth muscle, did not abolish the membrane potential oscillations but did alter their temporal characteristics.


2008 ◽  
Vol 294 (2) ◽  
pp. G372-G390 ◽  
Author(s):  
Sushil K. Sarna

The proposed functions of the interstitial cells of Cajal (ICC) are to 1) pace the slow waves and regulate their propagation, 2) mediate enteric neuronal signals to smooth muscle cells, and 3) act as mechanosensors. In addition, impairments of ICC have been implicated in diverse motility disorders. This review critically examines the available evidence for these roles and offers alternate explanations. This review suggests the following: 1) The ICC may not pace the slow waves or help in their propagation. Instead, they may help in maintaining the gradient of resting membrane potential (RMP) through the thickness of the circular muscle layer, which stabilizes the slow waves and enhances their propagation. The impairment of ICC destabilizes the slow waves, resulting in attenuation of their amplitude and impaired propagation. 2) The one-way communication between the enteric neuronal varicosities and the smooth muscle cells occurs by volume transmission, rather than by wired transmission via the ICC. 3) There are fundamental limitations for the ICC to act as mechanosensors. 4) The ICC impair in numerous motility disorders. However, a cause-and-effect relationship between ICC impairment and motility dysfunction is not established. The ICC impair readily and transform to other cell types in response to alterations in their microenvironment, which have limited effects on motility function. Concurrent investigations of the alterations in slow-wave characteristics, excitation-contraction and excitation-inhibition couplings in smooth muscle cells, neurotransmitter synthesis and release in enteric neurons, and the impairment of the ICC are required to understand the etiologies of clinical motility disorders.


2007 ◽  
Vol 293 (2) ◽  
pp. G438-G445 ◽  
Author(s):  
Lei Sha ◽  
Gianrico Farrugia ◽  
W. Scott Harmsen ◽  
Joseph H. Szurszewski

The aims of this study were to quantify the change in resting membrane potential (RMP) across the thickness of the circular muscle layer in the mouse and human small intestine and to determine whether the gradient in RMP is dependent on the endogenous production of carbon monoxide (CO). Conventional sharp glass microelectrodes were used to record the RMPs of circular smooth muscle cells at different depths in the human small intestine and in wild-type, HO2-KO, and W/WV mutant mouse small intestine. In the wild-type mouse and human intestine, the RMP of circular smooth muscle cells near the myenteric plexus was −65.3 ± 2 mV and −58.4 ± 2 mV, respectively, and −60.1 ± 2 mV and −49.1 ± 1 mV, respectively, in circular smooth muscle cells at the submucosal border. Oxyhemoglobin (20 μM), a trapping agent for CO, and chromium mesoporphyrin IX, an inhibitor of heme oxygenase, abolished the transwall gradient. The RMP gradients in mouse and human small intestine were not altered by NG-nitro-l-arginine (200 μM). No transwall RMP gradient was found in HO2-KO mice and W/WV mutant mice. TTX (1 μM) and 1H-[1,2,4-]oxadiazolo[4,3-a]quinoxalin-1-one (10 μM) had no effect on the RMP gradient. These data suggest that the gradient in RMP across the thickness of the circular muscle layer of mouse and human small intestine is CO dependent.


2021 ◽  
Vol 71 (1) ◽  
Author(s):  
Shin-Ichiro Karaki ◽  
Ryo Tanaka

AbstractColonic motor activity is important for the formation and propulsion of feces. The production of prostaglandins (PGs) in colonic tissue is considered to play a critical role in the generation and regulation of colonic motility. In this study, we investigated the inhibitory effects of PGE2 and selective agonists of four EP receptors on the spontaneous phasic contractions, called ‘giant contractions’ (GCs), of mucosa-free circular smooth muscle strips from the rat middle colon. Neural blockade with tetrodotoxin (TTX) increased the frequency and amplitude of the GCs by about twofold. However, inhibiting PG production with piroxicam reduced the GC frequency in the presence of TTX, but did not affect the GC amplitude. In the presence of both TTX and piroxicam, exogenous PGE2 and each EP receptor agonist were cumulatively added to the tissue bath. In this setting, PGE2, the EP2 agonist ONO-AE1-259, and the EP4 agonist ONO-AE1-329, but not the EP1 agonist ONO-AE-DI-004 or the EP3 agonist ONO-AE-248, concentration-dependently reduced the GC frequency and amplitude. The PGE2-induced inhibition of GC frequency and amplitude was inhibited by the EP4 antagonist ONO-AE3-208, but not by the EP1/2 antagonist AH6809. Immunohistochemistry revealed the EP2 and EP4 receptors were localized in perinuclear sites in circular smooth muscle cells. EP2 immunoreactivity was also located in GFAP-immunoreactive enteroglia, whereas EP4 immunoreactivity was also located in HU (embryonic lethal, abnormal vision [ELAV] protein; a marker of all myenteric neurons)-immunoreactive myenteric nerve cell bodies. These results suggest that the PGs produced in the colonic tissue inhibit the GC frequency and amplitude of circular muscle in the rat middle colon, and is mediated by EP4 receptors expressed in the smooth muscle cells.


1990 ◽  
Vol 68 (11) ◽  
pp. 1437-1446 ◽  
Author(s):  
M. S. Faussone-Pellegrini ◽  
C. Cortesini ◽  
D. Pantalone

The circular muscle layer of the human caecum and ascending colon is clearly subdivided into two portions: an outer one which includes the bulk of the circular muscle layer, and an inner one made up of only six to eight rows of cells. In the right transverse colon no demarcation can be observed, but a difference exists between the innermost and the outermost cells, since those of the two innermost rows possess some peculiarities with regard to the sarcoplasmic reticulum, glycogen particles, caveolae, and intercellular junctions. In the left part of the colon, the circular muscle layer is also divided into two portions. In fact, the innermost smooth muscle cells still possess peculiar morphologies, progressively increase in number, and become separate from each other making up a superficial muscle network. A fibrous lamella, along and inside which a ganglionated nerve plexus runs, is strictly apposed to the submucosal border of the circular muscle layer of the entire colonic length. A second nerve plexus runs between the two portions of the circular muscle layer. Both these plexuses are accompanied by interstitial cells of Cajal in the right colon only. The peculiar organization of the entire submucosal border of the human colonic circular muscle layer distinguishes it from other parts of the gut and probably represents a structural basis for control of human colonic motility. The presence of putative pacemaker cells (interstitial cells and peculiar smooth muscle cells) indicates that the inner border of human colonic circular muscle layer possesses pacemaking activities. Moreover, the interstitial cell – smooth muscle cell ratio differs depending on the colonic level; two main regions can be identified: the right and the left colon. Consequently, we might expect regional variation in pacemaking.Key words: smooth muscle cells, interstitial cells of Cajal, human colon, ultrastructure.


1984 ◽  
Vol 246 (3) ◽  
pp. G305-G315 ◽  
Author(s):  
E. E. Daniel ◽  
V. Posey-Daniel

The structures of the lower esophageal sphincter (LES) and body circular muscle (BCM) from opossum were compared as to neural and muscular structures and the structural relations of interstitial cells of Cajal to nerves and muscle cells. Both LES and BCM were densely innervated by nerves with varicosities containing many small agranular vesicles and a few large granular vesicles. These nerves were more closely related structurally to the interstitial cells of Cajal than to smooth muscle cells. More gap junctions were observed between smooth muscle cells and between interstitial cells of Cajal and smooth muscle cells in BCM than in LES. Those between smooth muscle cells were larger in BCM. Complete relaxation of the LES strip by isoproterenol reduced these differences but did not eliminate them. The finding that interstitial cells of Cajal often had gap-junction contacts to smooth muscle and close associations with nerves is consistent with the hypothesis that interstitial cells are intercalated between the nerves and muscles and may mediate nerve responses. These findings also suggest that LES muscle cells may be less well coupled electrically than BCM muscle cells.


1999 ◽  
Vol 277 (6) ◽  
pp. C1284-C1290 ◽  
Author(s):  
Hamid I. Akbarali ◽  
Hemant Thatte ◽  
Xue Dao He ◽  
Wayne R. Giles ◽  
Raj K. Goyal

An inwardly rectifying K+ conductance closely resembling the human ether-a-go-go-related gene (HERG) current was identified in single smooth muscle cells of opossum esophageal circular muscle. When cells were voltage clamped at 0 mV, in isotonic K+ solution (140 mM), step hyperpolarizations to −120 mV in 10-mV increments resulted in large inward currents that activated rapidly and then declined slowly (inactivated) during the test pulse in a time- and voltage- dependent fashion. The HERG K+ channel blockers E-4031 (1 μM), cisapride (1 μM), and La3+ (100 μM) strongly inhibited these currents as did millimolar concentrations of Ba2+. Immunoflourescence staining with anti-HERG antibody in single cells resulted in punctate staining at the sarcolemma. At membrane potentials near the resting membrane potential (−50 to −70 mV), this K+ conductance did not inactivate completely. In conventional microelectrode recordings, both E-4031 and cisapride depolarized tissue strips by 10 mV and also induced phasic contractions. In combination, these results provide direct experimental evidence for expression of HERG-like K+ currents in gastrointestinal smooth muscle cells and suggest that HERG plays an important role in modulating the resting membrane potential.


2018 ◽  
Vol 125 (4) ◽  
pp. 1090-1096 ◽  
Author(s):  
Alan L. James ◽  
Peter B. Noble ◽  
Su-Ann Drew ◽  
Thais Mauad ◽  
Tony R. Bai ◽  
...  

In asthma, it is unclear if the airway smooth muscle cells proliferate more or are increased at the onset of asthma and remain stable. This study aimed to compare smooth muscle cell proliferation in individuals with and without asthma and correlate proliferation rates with cell size and number and with granulocytic airway inflammation. Postmortem airway sections were labeled with proliferating cell nuclear antigen (PCNA) and percent positive muscle cells calculated. On the same sections, smooth muscle cell size and number and the number of eosinophils and neutrophils were estimated and compared in cases of nonfatal ( n = 15) and fatal ( n = 15) asthma and control subjects ( n = 15). The %PCNA+ muscle cells was not significantly different in fatal (29.4 ± 7.7%, mean ± SD), nonfatal asthma (28.6 ± 8.3%), or control subjects (24.6 ± 6.7%) and not related to mean muscle cell size ( r = 0.09), number ( r = 0.36), thickness of the muscle layer ( r = 0.05), or eosinophil numbers ( r = 0.04) in the asthma cases. These data support the hypothesis that in asthma the increased thickness of the smooth muscle layer may be present before or at the onset of asthma and independent of concurrent granulocytic inflammation or exacerbation. NEW & NOTEWORTHY There is debate regarding the origins of the increased airway smooth muscle in asthma. It may be independent of inflammation or arise as a proliferative response to inflammation. The present study found no increase in the proportion of proliferating smooth muscle cells in asthma and no relation of proliferation to numbers of airway smooth muscle cells or inflammation. These results support a stable increase in smooth muscle in asthma that is independent of airway inflammation.


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