Decrease in activity of smooth muscle L-type Ca2+ channels and its reversal by NF-κB inhibitors in Crohn's colitis model

2003 ◽  
Vol 285 (3) ◽  
pp. G483-G493 ◽  
Author(s):  
Kazuya Kinoshita ◽  
Koichi Sato ◽  
Masatoshi Hori ◽  
Hiroshi Ozaki ◽  
Hideaki Karaki
Keyword(s):  
Smooth Muscle ◽  
Crohn’S Disease ◽  
Crohn's Disease ◽  
Current Density ◽  
Smooth Muscles ◽  
Circular Muscle ◽  
Rat Colon ◽  
Trinitrobenzenesulfonic Acid ◽  
Circular Smooth Muscle ◽  
Colonic Cells

We investigated the mechanisms of dysmotility of the colonic circular muscle of the Crohn's disease rat model. Contractions induced by KCl, carbachol, and Bay K 8644 were decreased in circular smooth muscles isolated from 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis rat colon. However, the absolute force and Ca2+ sensitivity of contractile proteins were not affected as assessed in α-toxin permeabilized smooth muscle. The current density of the L-type Ca2+ channel in circular smooth muscle cells was significantly decreased in the TNBS-treated colonic cells. However, expressions of the L-type Ca2+ channel mRNA and protein did not differ between control and TNBS-treated preparations. Pretreatment with the NF-κB inhibitors pyrrolidinedithiocarbamate and sulfasalazine partially recovered the decreased contractility and current density of the L-type Ca2+ channel by TNBS treatment. These results suggest that the decrease in the contraction of circular smooth muscle isolated from TNBS-induced colitis rat colon, which may be related to gut dysmotility in Crohn's disease, is attributable to the decreased activity of the L-type Ca2+ channel. The dysfunction of the L-type Ca2+ channel may be mediated by NF-κB-dependent pathways.

scholarly journals Role of PGE2 in colonic motility: PGE2 attenuates spontaneous contractions of circular smooth muscle via EP4 receptors in the rat colon

2021 ◽  
Vol 71 (1) ◽  
Author(s):  
Shin-Ichiro Karaki ◽  
Ryo Tanaka
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Critical Role ◽  
Colonic Motility ◽  
Protein A ◽  
Circular Muscle ◽  
Muscle Cells ◽  
Rat Colon ◽  
Colonic Tissue ◽  
Circular Smooth Muscle

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.

scholarly journals Epigenetic modification of intestinal smooth muscle cell phenotype during proliferation

2018 ◽  
Vol 315 (5) ◽  
pp. C722-C733 ◽  
Author(s):  
Quinn A. Bonafiglia ◽  
Sandra R. Lourenssen ◽  
David J. Hurlbut ◽  
Michael G. Blennerhassett
Keyword(s):  
Smooth Muscle ◽  
Crohn’S Disease ◽  
Crohn's Disease ◽  
Cell Lines ◽  
Dna Methyltransferase ◽  
Epigenetic Modification ◽  
Similar Process ◽  
Rat Colon ◽  
Intestinal Smooth Muscle ◽  
Stricture Formation

Inflammation causes proliferation of intestinal smooth muscle cells (ISMC), contributing to a thickened intestinal wall and to stricture formation in Crohn’s disease. Proliferation of ISMC in vitro and in vivo caused decreased expression of marker proteins, but the underlying cause is unclear. Since epigenetic change is important in other systems, we used immunocytochemistry, immunoblotting, and quantitative PCR to examine epigenetic modification in cell lines from rat colon at low passage or after extended growth to evaluate phenotype. Exposure to the histone deacetylase (HDAC) inhibitor trichostatin A or the DNA methyltransferase inhibitor 5-azacytidine reversed the characteristic loss of phenotypic markers among high-passage cell lines of ISMC. Expression of smooth muscle actin and smooth muscle protein 22, as well as functional expression of the neurotrophin glial cell line-derived neurotrophic factor, was markedly increased. Increased expression of muscarinic receptor 3 and myosin light chain kinase was correlated with an upregulated response to cholinergic stimulation. In human ISMC (hISMC) lines from the terminal ileum, phenotype was similarly affected by extended proliferation. However, in hISMC from resected Crohn’s strictures, we observed a significantly reduced contractile phenotype compared with patient-matched intrinsic controls that was associated with increased patient-specific expression of DNA methyltransferase 1, HDAC2, and HDAC5. Therefore, protracted growth causes epigenetic alterations that account for an altered phenotype of ISMC. A similar process may promote stricture formation in Crohn’s disease, where the potential for halting progression, or even reversal, of disease through control of phenotypic modulation may become a novel treatment option.

Nitric oxide mediates outward potassium currents in opossum esophageal circular smooth muscle

1996 ◽  
Vol 270 (6) ◽  
pp. G932-G938 ◽  
Author(s):  
J. Jury ◽  
K. R. Boev ◽  
E. E. Daniel
Keyword(s):  
Nitric Oxide ◽  
Smooth Muscle ◽  
Circular Muscle ◽  
Outward Current ◽  
Equilibrium Potential ◽  
Patch Clamp Technique ◽  
Pipette Solution ◽  
Whole Cell ◽  
Circular Smooth Muscle ◽  
Outward Currents

Single smooth muscle cells from the opossum body circular muscle were isolated and whole cell currents were characterized by the whole cell patch-clamp technique. When the cells were held at -50 mV and depolarized to 70 mV in 20-mV increments, initial small inactivating inward currents were evoked (-30 to 30 mV) followed by larger sustained outward currents. Depolarization from a holding potential of -90 mV evoked an initial fast inactivating outward current sensitive to 4-aminopyridine but not to high levels of ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA). The outward currents reversed near K+ equilibrium potential and were abolished when KCl was replaced by CsCl in the pipette solution. The sustained outward current was inhibited by quinine and cesium. High EGTA in the pipette solution reduced but did not abolish the sustained outward currents, suggesting that both Ca(2+)-dependent and -independent currents were evoked. The nitric oxide (NO)-releasing agents Sin-1 and sodium nitroprusside increased outward K+ currents. High levels of EGTA in the pipette solution abolished the increase in outward current induced by Sin-1. The presence of cyclopiazonic acid, an inhibitor of the sarcoplasmic reticulum (SR) Ca2+ pump, blocked the effects of NO-releasing agents. We conclude that NO release activates K+ outward currents in opossum esophagus circular muscle, which may depend on Ca2+ release from the SR stores.

Plasticity of KIR channels in human smooth muscle cells from internal thoracic artery

2003 ◽  
Vol 284 (6) ◽  
pp. H2325-H2334 ◽  
Author(s):  
Tom Karkanis ◽  
Shaohua Li ◽  
J. Geoffrey Pickering ◽  
Stephen M. Sims
Keyword(s):  
Smooth Muscle ◽  
Current Density ◽  
Internal Thoracic Artery ◽  
Smooth Muscles ◽  
Vascular Smooth Muscles ◽  
Rt Pcr ◽  
Regulation Of Proliferation ◽  
Negative Membrane Potential ◽  
Inwardly Rectifying ◽  
Contractile Cells

Inwardly rectifying K+ (KIR) currents are present in some, but not all, vascular smooth muscles. We used patch-clamp methods to examine plasticity of this current by comparing contractile and proliferative phenotypes of a clonal human vascular smooth muscle cell line. Hyperpolarization of cells under voltage clamp elicited a large inward current that was selective for K+ and blocked by Ba2+. Current density was greater in proliferative compared with contractile cells (−4.5 ± 0.9 and −1.4 ± 0.3 pA/pF, respectively; P < 0.001). RT-PCR of mRNA from proliferative cells identified transcripts for Kir2.1 and Kir2.2 but not Kir2.3 potassium channels. Western blot analysis demonstrated greater expression of Kir2.1 protein in proliferative cells, consistent with the higher current density. Proliferative cells displayed a more negative membrane potential than contractile cells (−71 ± 2 and −35 ± 4 mV, respectively; P < 0.001). Ba2+ depolarized all cells, whereas small increases in extracellular K+ concentration elicited hyperpolarization only in contractile cells. Ba2+ inhibited [3H]thymidine incorporation, indicating a possible role for KIR channels in the regulation of proliferation. The phenotype-dependent plasticity of KIR channels may have relevance to vascular remodeling.

Are gap junctions necessary for cell-to-cell coupling of smooth muscle?: an update

1992 ◽  
Vol 70 (4) ◽  
pp. 481-490 ◽  
Author(s):  
R. E. Garfield ◽  
G. Thilander ◽  
M. G. Blennerhassett ◽  
N. Sakai
Keyword(s):  
Smooth Muscle ◽  
Gap Junctions ◽  
Current Knowledge ◽  
Smooth Muscles ◽  
Cell Communication ◽  
Circular Muscle ◽  
Cell Coupling ◽  
And Function ◽  
Longitudinal Layer ◽  
Cell Cell

Earlier, it was questioned whether gap junctions (GJs) were necessary for cell–cell communication in smooth muscle, and GJs were not seen in some smooth muscles. We reexamined this question in the myometrium and in intestinal smooth muscle, in light of current knowledge of the presence and function of GJs. In the uterus, numerous studies show that an increase in GJ number is associated with the onset of delivery and is required for effective parturition. In all cases, this increase in GJ number and the changes in uterine contractility were correlated with increased electrical and metabolic coupling. Evidence for the much smaller, but detectable, degree of electrical coupling in the preterm uterus is explained by the small (but again detectable) number of GJs present. In the intestine, GJs are readily detected in the circular muscle layer but have not been described in the adjacent longitudinal layer. While our immunohistochemical studies failed to detect GJs in the longitudinal layer, this may not be adequate to prove their absence. Therefore, current knowledge of GJ number and function is adequate to explain cell–cell coupling in the uterus. Although it remains uncertain whether GJs are absent from the longitudinal muscle of the intestine, there is no definitive evidence that cell–cell coupling can occur by means other than GJs.Key words: gap junctions, myometrium, connexins, smooth muscle, cell communication.

Role of HERG-like K+ currents in opossum esophageal circular smooth muscle

1999 ◽  
Vol 277 (6) ◽  
pp. C1284-C1290 ◽  
Author(s):  
Hamid I. Akbarali ◽  
Hemant Thatte ◽  
Xue Dao He ◽  
Wayne R. Giles ◽  
Raj K. Goyal
Keyword(s):  
Smooth Muscle ◽  
Membrane Potential ◽  
Smooth Muscle Cells ◽  
Single Cells ◽  
Circular Muscle ◽  
Muscle Cells ◽  
Resting Membrane Potential ◽  
Channel Blockers ◽  
Circular Smooth Muscle ◽  
Inward Currents

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.

Myosin phosphorylation and contraction of feline esophageal smooth muscle

1985 ◽  
Vol 249 (1) ◽  
pp. C9-C14 ◽  
Author(s):  
N. W. Weisbrodt ◽  
R. A. Murphy
Keyword(s):  
Smooth Muscle ◽  
Mechanical Activation ◽  
Smooth Muscles ◽  
Circular Muscle ◽  
Electrical Field Stimulation ◽  
Muscle Layer ◽  
Field Stimulation ◽  
Shortening Velocity ◽  
Myosin Phosphorylation ◽  
Isotonic Shortening

We tested the hypothesis that phosphorylation of the 20,000-Da light chain of myosin (LC 20) is related to mechanical activation of esophageal smooth muscle. Circular muscle layer strips of cat esophagus were taken from the lower esophageal sphincter (LES) and the distal esophageal body (EB). The LES strips developed tone spontaneously, and the EB strips were tonically contracted with carbachol. Both tissues relaxed in response to electrical-field stimulation. Phosphorylation of the LC 20 was determined in tissues quick-frozen during relaxation and during stress redevelopment after cessation of field stimulation. Stress and phosphorylation levels were low after 30 s of field stimulation, and a rapid contraction followed field stimulation. Phosphorylation in the LES increased from 0.043 +/- 0.029 to 0.328 +/- 0.043 mol Pi/mol LC 20 within 10 s after stimulation of the inhibitory nerves was terminated, while stress was still rising rapidly. Phosphorylation in the LES then declined to a steady-state value of 0.162 +/- 0.034 mol Pi/mol LC 20 after 10 min. Isotonic shortening velocities at a constant afterload following a quick release showed changes with time that were proportional to the level of phosphorylation. This was also true for values of maximal shortening velocity estimated for zero external load and for the rate of stress redevelopment after a step shortening. Comparable measurements were made in the carbachol-contracted EB. These results indicate that visceral smooth muscles, which normally function tonically (LES) or phasically (EB), exhibit an initial rapid mechanical activation associated with myosin phosphorylation.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrophysiological analysis of responses to intrinsic nerves in circular muscle of opossum esophageal muscle

1988 ◽  
Vol 254 (1) ◽  
pp. G107-G116 ◽  
Author(s):  
R. Serio ◽  
E. E. Daniel
Keyword(s):  
Smooth Muscle ◽  
Circular Muscle ◽  
Electrical Field Stimulation ◽  
High Frequency Stimulation ◽  
Organ Bath ◽  
Circular Smooth Muscle ◽  
Time To Peak ◽  
Frequency Stimulation ◽  
Sucrose Gap ◽  
Cholinergic Agents

The nerve-mediated responses to electrical field stimulation (EFS) along the opossum esophageal circular smooth muscle were studied with the sucrose-gap recording technique. Strips from 1-2, 4-5, 7-8, and 10-11 cm above the lower esophageal sphincter were stimulated with short-train (300 ms) and long-train (3 s) durations at 29 degrees C. The response always consisted of a hyperpolarization [inhibitory junction potentials (IJP)] followed by an "off depolarization" often associated with spike potentials and mechanical contraction. Proximal to distal differences in the characteristics of the evoked responses were found, i.e., increasing amplitude, duration and time to peak hyperpolarization of the IJP, increasing latency, and amplitude of the off depolarization. Neither atropine, scopolamine, physostigmine, nor guanethidine altered these characteristics substantially. Circular strips of muscularis externa, studied in the organ bath at 37 degrees C using 10-s EFS trains at 5-40 pps, produced off contractions, enhanced by physostigmine and reduced by atropine. High-frequency stimulation occasionally initiated small persistent intrastimulus ("on") responses; some were sensitive to cholinergic agents, but there was no gradient in the delay in their onset. Atropine-insensitive and tetrodotoxin-potentiated transient on responses were occasionally detected. We conclude that only the noncholinergic, nonadrenergic innervation provides a functional intrinsic innervation directly to the opossum esophagus circular smooth muscle when nerves are activated by EFS.

Effect of cold temperature on membrane potential responses in opossum esophageal circular muscle

1989 ◽  
Vol 257 (4) ◽  
pp. G637-G643
Author(s):  
D. Kauvar ◽  
J. Crist ◽  
R. K. Goyal
Keyword(s):  
Smooth Muscle ◽  
Membrane Potential ◽  
Circular Muscle ◽  
Electrical Field Stimulation ◽  
Cold Temperature ◽  
Resting Membrane Potential ◽  
Spike Potential ◽  
Circular Smooth Muscle ◽  
Time To Peak ◽  
Proximal Site

The effects of cold temperature on resting membrane potential (RMP) and membrane potential responses to depolarizing electrical current and intramural nerve stimulation were examined in opossum esophageal circular smooth muscle. Intracellular recordings were made in smooth muscle strips obtained from 7 to 8 cm (proximal site) and 1 to 2 cm (distal site) above the lower esophageal sphincter. RMP was not affected by changes in temperature between 34 and 22 degrees C. Cooling caused progressive inhibition of the amplitude and a slight increase in the duration of the spike potential produced by depolarizing current. Cooling did not modify the threshold for spike potential generation but decreased the spike amplitude from 34.0 +/- 0.5 mV at 34 degrees C to 14.1 +/- 2.2 mV at 22 degrees C (P less than 0.01). Electrical field stimulation with single electrical pulses (1.0 ms) produced tetrodotoxin-sensitive biphasic membrane responses consisting of initial hyperpolarization, or an inhibitory junction potential followed by depolarization that increased in amplitude as temperature was decreased from 34 to 26 degrees C and then decreased in amplitude as temperature was further decreased. At both proximal and distal sites cooling from 34 to 22 degrees C caused more than a twofold increase in the duration of hyperpolarization and time to peak depolarization. However, the increase in the absolute time of the duration of hyperpolarization and the time to peak depolarization was significantly greater at the distal than proximal esophageal site. Cooling to 16 degrees C decreased RMP and nearly abolished the biphasic membrane potential response.(ABSTRACT TRUNCATED AT 250 WORDS)

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