scholarly journals Functional Coordination of Motor Activity in Colonic Smooth Muscles in Rat Experimental Model

2011 ◽  
pp. 659-666 ◽  
Author(s):  
N. NEDIALKOVA ◽  
G. STAVREVA ◽  
N. NEGREV ◽  
C. IVANCHEVA ◽  
R. RADOMIROV
Keyword(s):  
Motor Activity ◽  
Longitudinal Muscle ◽  
Smooth Muscles ◽  
Circular Muscle ◽  
Electrical Field Stimulation ◽  
High Amplitude ◽  
Middle Part ◽  
Organ Bath ◽  
Motor Responses ◽  
Reflex Pathways

Spontaneous and electrically-elicited motor activity was recorded by triple organ bath in rat segment-model preparation as display of excitation of local nerve networks and ascending or descending reflex pathways underlying contractile potency and functional coordination of colonic longitudinal and circular muscles. Spontaneous high-amplitude contractions, but not relaxations, appeared synchronously in both muscles. Electrical field stimulation applied to proximal or distal part of segments elicited both tetrodotoxin (0.1 µM)-sensitive local motor responses of the stimulated part and ascending or descending motor responses of the contralateral, nonstimulated part of the preparations. Contractions characterized the local response of longitudinal muscle. The circular muscle responded with relaxation followed by contraction. Synchronous ascending contractions and descending contraction of the longitudinal muscle and relaxation followed by contraction of the circular muscle were observed when the middle part of segments was stimulated, thus indicating that locally-induced nerve excitation propagated via intrinsic ascending or descending nerve pathways that could be synchronously coactivated by one and the same stimulus. The ascending motor responses were more pronounced and the motor responses of longitudinal muscle were expressed more than those of circular muscle suggesting an essential role of ascending reflex pathways and longitudinal muscle in the coordinated motor activity of colon.

scholarly journals Ascending Excitatory and Inhibitory Motor Activity of Colonic Longitudinal and Circular Muscles in Rat Model

2019 ◽  
Vol 12 (1) ◽  
pp. 10-18
Author(s):  
Zornitsa V. Gorcheva ◽  
Galya Ts. Stavreva ◽  
Negrin N. Negrev ◽  
Radomir G. Radomirov
Keyword(s):  
Motor Activity ◽  
Electrical Field Stimulation ◽  
Rat Colon ◽  
Organ Bath ◽  
Motor Responses ◽  
Reflex Pathways ◽  
Atropine Treatment ◽  
Myenteric Ganglia ◽  
Isolated Rat Colon

Summary In this experiment we studied the role of excitatory and inhibitory neurotransmissions in the ascending reflex pathways in isolated rat colon. Partitioned organ bath, electrical field stimulation (EFS), drugs and isolated preparations were used to evaluate motor activity of (LM) and circular muscles (CM). Ascending motor responses of LM and CM were frequency-dependent contraction, significantly more expressed in LM. Atropine (0.3 µM) decreased ascending contractions of LM. During atropine treatment spantide (0.1 µM) further suppressed ascending contractile motor responses. In the presence of atropine, L-NNA (0.5 mM) restored ascending contractions of LM, while contractions were strongly depressed after addition of L-arginine (0.5 mM). Ascending response in CM, caused by atropine, consisted of an initial relaxation followed by contraction. Spantide decreased the contraction. L-NNA reduced the relaxation and significantly restored the atropine-influenced contraction, while L-arginine induced a deep relaxation of CM. The presence of ChAT, SP-containing nerve cell bodies and fibers and NADPH-diaphorase-reactive cell bodies and processes in myenteric ganglia were detected. The results indicated that nitric oxide is an important modulator of ascending cholinergic and tachykininergic excitation in colonic region of the large intestine of rats.

Excitatory and inhibitory responses of Oddi's sphincter in guinea pigs

1991 ◽  
Vol 260 (4) ◽  
pp. G615-G624 ◽  
Author(s):  
T. Hirose ◽  
Y. Ito
Keyword(s):  
Smooth Muscle ◽  
Action Potentials ◽  
Regional Differences ◽  
Longitudinal Muscle ◽  
Smooth Muscles ◽  
Central Area ◽  
Circular Muscle ◽  
Electrical Field Stimulation ◽  
Muscle Cells ◽  
Field Stimulation

We examined the intrinsic motor innervation of the guinea pig choledochoduodenal junction and actions of cholecystokinin octapeptide (CCK-OP) on contractile and membrane activity of circular and longitudinal smooth muscles from three different areas: close to the choledochal sphincter (I); central area in the ampulla (II); and close to the duodenal papilla (III). In response to electrical field stimulation, circular muscle strips showed an initial twitchlike contraction followed by relaxation in areas I and II and only a transient relaxation in the muscle strips prepared from area III. In the longitudinal strips, the regional differences in response to the field stimulation were not prominent, and biphasic twitchlike contractions were observed in areas I, II, and III. Electric field stimulation evoked excitatory junction potentials (EJPs), inhibitory junction potentials (IJPs), or biphasic membrane response (initial EJP followed by an IJP) in the circular and longitudinal smooth muscle cells. Prominent regional differences were observed in areas I, II, and III. Namely, in area III both the circular and longitudinal muscle layers IJPs predominated, whereas in area I the response was predominantly excitatory. CCK-OP (greater than 10-8M) evoked repetitive action potentials in the circular muscle cells, and CCK-OP increased the frequency of slow waves or the spontaneous action potentials in longitudinal muscle cells. CCK-OP enhanced the amplitude of the IJPs and EJPs in both muscle layers. It would thus appear that bile flow is controlled by complex combinations of contraction and relaxation of the smooth muscle that may be due to regional differences in excitatory and inhibitory innervations.

Evidence supporting presence of two pacemakers in rat colon

2001 ◽  
Vol 281 (1) ◽  
pp. G255-G266 ◽  
Author(s):  
Lídia Plujà ◽  
Elena Albertí ◽  
Ester Fernández ◽  
Hanne Birte Mikkelsen ◽  
Lars Thuneberg ◽  
...  
Keyword(s):  
Longitudinal Muscle ◽  
Activity Patterns ◽  
Low Frequency ◽  
Circular Muscle ◽  
High Amplitude ◽  
Mechanical Activity ◽  
Rat Colon ◽  
Organ Bath ◽  
Cyclic Activity ◽  
Immunohistochemical Studies

Intracellular microelectrodes and organ bath techniques were used to study spontaneous cyclic electrical and mechanical activity in the rat colon. Electron microscopy and immunohistochemical studies showed two major populations of interstitial cells of Cajal (ICC): one associated with Auerbach's plexus (ICC-AP) and one with the submuscular plexus (ICC-SMP). The ICC-SMP network partly adhered to the submucosa when removed and was generally strongly damaged after separation of musculature and submucosa. Similarly, longitudinal muscle removal severely damaged AP. Two electrical and mechanical activity patterns were recorded: pattern A, low-frequency (0.5–1.5 cycles/min), high-amplitude oscillations; and pattern B, high-frequency (13–15 cycles/min), low-amplitude oscillations. Pattern A was recorded in preparations with intact AP but absent in those without intact AP. Pattern B was recorded in preparations with intact SMP but was absent in those lacking SMP. With full-thickness strips, the superimposed patterns A and B were recorded in circular muscle. When longitudinal muscle mechanical activity was recorded, only pattern A was present. We conclude that two pacemakers regulate rat colonic cyclic activity: the ICC-SMP network (responsible for cyclic slow waves and small-amplitude contractions) and the ICC-AP network (which may drive the cyclic depolarizations responsible for high-amplitude contractions). This is the first report showing consistent slow wave activity in the rodent colon.

scholarly journals Relaxant effect of quercetin on rabbit isolated bladder smooth muscles contractions

2020 ◽  
Vol 10 (1) ◽  
pp. 61-67
Author(s):  
Hassan Sadraei ◽  
Sabihe Tabesh
Keyword(s):  
Smooth Muscles ◽  
Electrical Field Stimulation ◽  
Negative Control ◽  
Flavonoid Compound ◽  
Drug Candidate ◽  
Control Group ◽  
Organ Bath ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Relaxant Effect

Introduction: Quercetin is a flavonoid compound found in many medicinal plants. Antispasmodic effect of quercetin has been reported in ileum and uterus smooth muscles but not in bladder. Therefore, the objective of this research was to investigate relaxant effect of quercetin in rabbit isolated bladder. Methods: Male rabbit was asphyxiated with carbon dioxide and then sacrificed. The whole bladder was dissected out and placed in oxygenated Tyrode’s solution. Isolated bladder was cut into longitudinal strips and placed in an organ bath for contraction studies. Contractions were induced with KCl (20mM), acetylcholine (5μM) and electrical field stimulation (EFS). Full inhibitory concentration–response curve was constructed for quercetin following addition of above spasmogens. Quercetin was added into the organ bath with 2 fold increments in concentration until maximum response was achieved. Nifedipine was used as positive control group and equivalent volume of quercetin vehicle (water + DMSO) was used as negative control group.Results: Quercetin (4 μg/mL to 640 μg/mL) in a concentration dependent manner inhibited isolated bladder strips contracted by KCl (IC50=159±25 μg/mL), acetylcholine (IC50=43±9.1 μg/mL) and EFS (IC50=38±9.3 μg/mL). In the highest used concentration, quercetin completely removed contractile responses to KCl, acetylcholine and electrical filed stimulation (EFS). Nifedipine totally inhibited KCl response (IC50=115±36 ng/mL) but only partially inhibited acetylcholine and EFS responses. Conclusion: These results confirm the relaxant effect of quercetin on rabbit bladder and if similar effects are seen in human studies, then quercetin would be a suitable drug candidate to be investigated for bladder incontinence.

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.

Differential effects of [Gln4]neurotensin on circular and longitudinal muscle of dog ileum in vitro

1987 ◽  
Vol 253 (4) ◽  
pp. G566-G572
Author(s):  
M. Karaus ◽  
K. R. Prasad ◽  
S. K. Sarna ◽  
I. M. Lang
Keyword(s):  
Longitudinal Muscle ◽  
Contractile Activity ◽  
Circular Muscle ◽  
Electrical Field Stimulation ◽  
Cholinergic Nerves ◽  
Differential Effects ◽  
Dose Dependent Fashion ◽  
Dose Dependent ◽  
Muscle Contractile

We studied the effects of neurotensin analogue [Gln4]-neurotensin on isolated dog ileal longitudinal and circular muscle strips. [Gln4]neurotensin stimulated the spontaneous contractile activity of the circular muscle but inhibited that of the longitudinal muscle in a dose-dependent fashion. Hexamethonium had no effect on the spontaneous longitudinal or circular muscle contractile activity. Atropine and tetrodotoxin (TTX) both inhibited the longitudinal muscle. Atropine had no effect on the circular muscle, but TTX stimulated it. The effects of [Gln4]neurotensin on the circular muscle were reduced but not completely abolished by atropine. The inhibition of the longitudinal muscle by [Gln4]neurotensin was not reduced by any of the above antagonists but was enhanced by atropine. Electrical field stimulation (10 Hz, 100 mA) stimulated the longitudinal muscle and inhibited or stimulated the circular muscle depending on the pulse width of the stimulus. These effects were unaffected by [Gln4]neurotensin. We conclude that [Gln4]neurotensin has differential effects on isolated muscle strips of the two muscle layers in the dog ileum. It stimulates the circular muscle partially through cholinergic nerves at preganglionic sites and partially through a direct myogenic effect. [Gln4]neurotensin inhibits the spontaneous activity of the longitudinal muscle presumably by reducing the excitability of cholinergic nerves at postganglionic sites.

Human isolated ileum: motor responses of the circular muscle to electrical field stimulation and exogenous neuropeptides

1990 ◽  
Vol 341 (3) ◽  
Author(s):  
CarloAlberto Maggi ◽  
Riccardo Patacchini ◽  
Paolo Santicioli ◽  
Sandro Giuliani ◽  
Damiano Turini ◽  
...  
Keyword(s):  
Circular Muscle ◽  
Electrical Field Stimulation ◽  
Field Stimulation ◽  
Electrical Field ◽  
Motor Responses

scholarly journals Effect of Matricaria chamomilla hydro-alcoholic and flavonoids rich extracts on rat isolated uterus

2020 ◽  
Vol 9 (1) ◽  
pp. 35-41
Author(s):  
Hassan Sadraei ◽  
Seyed Ebrahim Sajjadi ◽  
Gholamreza Asghari ◽  
Majid Khalili
Keyword(s):  
Smooth Muscles ◽  
Electrical Field Stimulation ◽  
Organ Bath ◽  
Alcoholic Extract ◽  
Matricaria Chamomilla ◽  
Spontaneous Movement ◽  
Medicinal Use ◽  
Pharmacological Studies ◽  
Increase Risk ◽  
Uterus Contraction

Introduction: Pharmacological studies confirm antispasmodic activities of chamomile (Matricaria chamomilla) extract on intestinal smooth muscles and it has been suggested that chamomile increases uterus tone, but so far there is no scientific studies which support this assumption. Therefore, this study was designed to determine spasmodic and spasmolytic activities of M. chamomilla extracts on rat isolated uterus. Methods: Hydro-alcoholic extract of M. chamomilla was prepared by maceration technique. Flavonoids rich extract was prepared by liquid in liquid extraction technique. The spasmodic effects of the extracts were assessed on spontaneously contracting rat uterus. The myorelaxant effect of M. chamomilla extracts was validated on isolated uterus contractions induced by KCl, acetylcholine (ACh), electrical field stimulation (EFS) and oxytocin. Results: Hydro-alcoholic extract of M. chamomilla (0.8 and 1.6 mg/mL) enhanced spontaneous movement of rat isolated uterus smooth muscle suspended in an organ bath. On the other hand, flavonoids rich fraction only diminished uterus contractile activities. Flavonoids rich extract of the plant at bath concentration ranges of 40 μg/mL to 400 μg/mL attenuated uterus response to ACh, KCl, EFS and oxytocin. The hydro-alcoholic extract of M. chamomilla at higher concentration ranges (250 μg/mL to 1.5 mg/mL) inhibited uterus contractions induced by the above spasmogens. Conclusion: The present study confirms both spasmodic and spasmolytic activities M. chamomilla hydro-alcoholic extract. Therefore, medicinal use of the crude extract of M. chamomilla may initiate uterus contraction which could increase risk of spontaneous miscarriage or premature parturition.

Characterization of the properties of canine colonic smooth muscle in culture

1993 ◽  
Vol 265 (5) ◽  
pp. C1433-C1442 ◽  
Author(s):  
M. J. Rogers ◽  
S. M. Ward ◽  
M. A. Horner ◽  
K. M. Sanders ◽  
B. Horowitz
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscles ◽  
Potential Gradient ◽  
Circular Muscle ◽  
Electrical Field Stimulation ◽  
Muscle Layer ◽  
Enteric Neurons ◽  
Resting Potential ◽  
Northern Analysis ◽  
Functional Components

We have developed and characterized an organ culture system that maintains the viability of colonic smooth muscles. Morphological, mechanical, electrical, and molecular properties of cultured canine colonic circular muscles were determined. Strips of circular muscle were cultured for up to 6 days. The smooth muscle phenotype was retained during culture; muscles contracted to agonists and responded to electrical field stimulation, suggesting that intrinsic nerves also survived in culture. Morphological analysis showed identifiable smooth muscle cells, enteric neurons, and interstitial cells, but some alterations in ultrastructure were also observed. Mechanical responses to acetylcholine suggested that the muscles developed supersensitivity during the culture period. The resting membrane potentials of cells near the submucosal surface of the circular muscle layer decreased from -82 mV on day 0 to -55 mV on day 3. Similar changes in the resting potential gradient occur when colonic muscles are treated with inhibitors of the Na(+)-K(+)-ATPase. Resting potentials of day 3 muscles remained constant in low external K+ (0.1 mM), suggesting little contribution of the pump to resting potential. Northern analysis of RNA from muscles cultured up to 6 days showed that the alpha 2-isoform of the pump decreased. The data suggest that organ-cultured strips of smooth muscle may provide a useful tool for evaluating electrical and mechanical events in conjunction with molecular analysis of functional components.

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