Miniature Excitatory Junction Potentials in the Somatic Muscle of the Earthworm, Pheretima Communissima, in Sodium Free Solution

1. Miniature excitatory junction potentials (m.e.j.p.s) could be recorded from the longitudinal muscle layer of earthworm in sodium-free solution. 2. The amplitude and frequency of the m.e.j.p.s indicated the diffuse innervation and random release of the chemical transmitter from the nerve terminals. 3. Generation of the m.e.j.p.s was prevented by treatment with D-tubocurarine, but not by atropine and picrotoxin. 4. Hyperpolarizations of the membrane by applications of inward current increased the frequency and amplitude of the m.e.j.p.s in sodium-free solution. 5. The reversal potential level for the m.e.j.p.s in sodium-free solution was -;20 mV., and this value was 20 mV. negative to that measured in physiological solution. Low-potassium solution shifted the reversal potential levels in a more negative and high-calcium in a less negative direction. 6. The change of the reversal potential produced by a tenfold change of the external potassium concentration was 24.5 mV., and that by change of the external calcium concentration was 17 mV.

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Rhythmic Electrical Activity in Stomach and Intestine of Toad

Journal of Experimental Biology ◽

10.1242/jeb.86.1.237 ◽

1980 ◽

Vol 86 (1) ◽

pp. 237-248

Author(s):

ALLEN MANGEL ◽

C. LADD PROSSER

Keyword(s):

Smooth Muscle ◽

Longitudinal Muscle ◽

Circular Muscle ◽

Sodium Concentration ◽

Muscle Layer ◽

Free Solution ◽

Longitudinal Muscle Layer ◽

Longitudinal Smooth Muscle ◽

Mammalian Intestine ◽

Periodic Changes

The intact stomach of the toad initiates rhythmic slow-spikes of 5–15 s duration and frequency of 3-5 min−1. The spontaneous electrical waves originate in the longitudinal muscle layer; isolated circular muscle is quiescent. Aboral conduction velocity is 0.12–0.9 mm s−1. Reduction of external sodium concentration from 89.5 to 15 mM produced no effect on slow spikes, although further reduction to 1.5 mM increased frequency and decreased amplitude. Slow-spikes were unaffected by ouabain or by incubation in potassium-free solution. When calcium in the medium was reduced, slow-spike amplitude and frequency decreased. Slow-spikes exhibited a change in amplitude of 16 mV per decade change in CaO2+; slow-spikes were eliminated at 10−8 M CaO2+ and by blockers of calcium conductance channels. Intact intestine of toad demonstrated slow-waves which resembled those of mammalian intestine. These were sensitive to changes in external sodium and were eliminated by 1 × 10−4M ouabain. It is suggested that rhythmic slow-spikes of longitudinal smooth muscle of amphibian stomach may result from periodic changes in Ca conductance whereas endogenous electrical waves of intestine may result from rhythmic extrusion of sodium.

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Inhibitory actions of eugenol on rat isolated ileum

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y02-117 ◽

2002 ◽

Vol 80 (9) ◽

pp. 901-906 ◽

Cited By ~ 21

Author(s):

José H Leal-Cardoso ◽

Saad Lahlou ◽

Andrelina N Coelho-de-Souza ◽

David N Criddle ◽

Glória I.B Pinto Duarte ◽

...

Keyword(s):

Smooth Muscle ◽

Methyl Ester ◽

Essential Oil ◽

Transmembrane Potential ◽

Longitudinal Muscle ◽

Direct Action ◽

Muscle Layer ◽

Free Solution ◽

Longitudinal Muscle Layer ◽

Rat Ileum

The effects of eugenol (12000 μM) on rat isolated ileum were studied. Eugenol relaxed the basal tonus (IC50 83 μM) and the ileum precontracted with 60 mM KCl (IC50 162 μM), an action unaltered by 0.5 μM tetrodotoxin, 0.2 mM NG-nitro-L-arginine methyl ester, 0.5 mM hexamethonium, and 1 μM indomethacin. Eugenol did not alter the resting transmembrane potential (Em) of the longitudinal muscle layer under normal conditions (5.0 mM K+) or in depolarised tissues. Eugenol reversibly inhibited contractions induced by submaximal concentrations of acetylcholine (ACh) and K+ (40 mM) with IC50 values of approximately 228 and 237 μM, respectively. Eugenol blocked the component of ACh-induced contraction obtained in Ca2+-free solution (0.2 mM EGTA) or in the presence of nifedipine (1 μM). Our results suggest that eugenol induces relaxation of rat ileum by a direct action on smooth muscle via a mechanism largely independent of alterations of Em and extracellular Ca2+ influx.Key words: essential oil, eugenol, ileum, smooth muscle, antispasmodic.

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Neuromuscular Transmission in the Longitudinal Layer of Somatic Muscle in the Earthworm

Journal of Experimental Biology ◽

10.1242/jeb.50.2.417 ◽

1969 ◽

Vol 50 (2) ◽

pp. 417-430

Author(s):

T. HIDAKA ◽

Y. ITO ◽

H. KURIYAMA ◽

N. TASHIRO

Keyword(s):

Time Course ◽

Longitudinal Muscle ◽

Chloride Concentration ◽

Reversal Potential ◽

Membrane Conductance ◽

Equilibrium Potential ◽

Muscle Fibres ◽

Free Solution ◽

Excitatory Junction Potentials ◽

Potential Level

1. The properties of the miniature inhibitory junction potentials (M.I.J.P.) and the inhibitory junction potentials (I.J.P.) elicited by nerve stimulation were investigated in longitudinal muscle fibres of the earthworm. 2. Histograms of the amplitudes(mean,0.71mV.) and the intervals (mean, 101 msec.) of the M.I.J.P. showed skew curves. 3. The polarity of the M.I.J.P. was reversed at about -60 mV. When the external chloride was substituted by glutamate the M.I.J.P. disappeared as an external chloride concentration of 15-20 mM, and further reduction reversed their polarity. 4. Picrotoxin blocked generation of the M.I.J.P. and the I.J.P. 5. The cross-over point of the current-voltage relation curves, with and without presence of GABA, occurred at a membrane potential of -54 mV. in potassium-free solution, and at -56 mV. in potassium-excess solution. 6. Iontophoretic application of GABA produced slow hyperpolarization. The equilibrium potential of the GABA-potential was about -60 mV. During the time course of the GABA-potentials an increase in the membrane conductance was observed. 7. Miniature excitatory junction potentials (M.E.J.P.) and excitatory junction potentials (E.J.P.) could be recorded from the longitudinal muscle, but the M.E.J.P. were rare. 8. D-tubocurarine, but not atropine, completely blocked the M.E.J.P. and E.J.P. Prostigmine enhanced their amplitude and duration. 9. The reversal potential level for the E.J.P. was about 0 mV. Sodium-free solution lowered the reversal potential level for the M.E.J.P. to -20 mV.

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Effects of Various Ions on the Resting and Active Membrane of the Somatic Muscle of the Earthworm

Journal of Experimental Biology ◽

10.1242/jeb.50.2.405 ◽

1969 ◽

Vol 50 (2) ◽

pp. 405-415

Author(s):

T. HIDAKA ◽

Y. ITO ◽

H. KURIYAMA ◽

N. TASHIRO

Keyword(s):

Calcium Concentration ◽

Longitudinal Muscle ◽

Potassium Concentration ◽

Resting Potential ◽

Somatic Muscle ◽

Membrane Potential Change ◽

Maximum Slope ◽

External Potassium ◽

Maximum Rate Of Rise ◽

External Calcium

1. The properties of the membrane, in both the resting and the active state, of the longitudinal muscle of the earthworm were studied under various ionic environments. 2. The maximum slope of the membrane potential change against a tenfold change in the external potassium concentration was 27 mV. in the presence of external sodium and 42 mV. in the absence of external sodium. 3. In the normal external potassium concentration the removal of sodium hyper-polarized the membrane from a normal resting potential of -36 to -58 mV. 4. Reduction of the external calcium concentration to a tenth of its normal value depolarized the membrane by about 16 mV. 5. In excess of external potassium the spike height and the after-hyperpolarization were decreased and the duration of the spike was prolonged. 6. In sodium-free solution spikes with an overshoot potential were generated both spontaneously and under the stimulus of an intracellularly depolarizing current. 7. The amplitude and the maximum rate of rise of the spike were dependent on the external calcium concentration, whether or not sodium was present externally. 8. Manganese modified the membrane activity by competition with calcium.

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Patch-clamp study of neurons and glial cells in isolated myenteric ganglia

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.2000.278.4.g644 ◽

2000 ◽

Vol 278 (4) ◽

pp. G644-G651 ◽

Cited By ~ 45

Author(s):

M. Hanani ◽

M. Francke ◽

W. Härtig ◽

J. Grosche ◽

A. Reichenbach ◽

...

Keyword(s):

Patch Clamp ◽

Glial Cells ◽

Muscle Layer ◽

Membrane Receptors ◽

Delayed Rectifier ◽

Longitudinal Muscle Layer ◽

Inward Currents ◽

Morphological Identity ◽

Clamp Study ◽

Myenteric Ganglia

Most of the physiological information on the enteric nervous system has been obtained from studies on preparations of the myenteric ganglia attached to the longitudinal muscle layer. This preparation has a number of disadvantages, e.g., the inability to make patch-clamp recordings and the occurrence of muscle movements. To overcome these limitations we used isolated myenteric ganglia from the guinea pig small intestine. In this preparation movement was eliminated because muscle was completely absent, gigaseals were obtained, and whole cell recordings were made from neurons and glial cells. The morphological identity of cells was verified by injecting a fluorescent dye by micropipette. Neurons displayed voltage-gated inactivating inward Na+ and Ca2+currents as well as delayed-rectifier K+ currents. Immunohistochemical staining confirmed that most neurons have Na+ channels. Neurons responded to GABA, indicating that membrane receptors were retained. Glial cells displayed hyperpolarization-induced K+ inward currents and depolarization-induced K+ outward currents. Glia showed large “passive” currents that were suppressed by octanol, consistent with coupling by gap junctions among these cells. These results demonstrate the advantages of isolated ganglia for studying myenteric neurons and glial cells.

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First reported case of per anal endoscopic myectomy (PAEM): A novel endoscopic technique for resection of lesions with severe fibrosis in the rectum

Endoscopy International Open ◽

10.1055/s-0042-122965 ◽

2017 ◽

Vol 05 (03) ◽

pp. E146-E150 ◽

Cited By ~ 1

Author(s):

David Rahni ◽

Takashi Toyonaga ◽

Yoshiko Ohara ◽

Francesco Lombardo ◽

Shinichi Baba ◽

...

Keyword(s):

Longitudinal Muscle ◽

Circular Muscle ◽

Muscle Layer ◽

Rectal Tumor ◽

Resection Margins ◽

Submucosal Layer ◽

Longitudinal Muscle Layer ◽

Circular Muscle Layer ◽

Tunneling Method ◽

Severe Fibrosis

Background and study aims A 54-year-old man was diagnosed with a rectal tumor extending through the submucosal layer. The patient refused surgery and therefore endoscopic submucosal dissection (ESD) was pursued. The lesion exhibited the muscle retraction sign. After dissecting circumferentially around the fibrotic area by double tunneling method, a myotomy was performed through the internal circular muscle layer, creating a plane of dissection between the internal circular muscle layer and the external longitudinal muscle layer, and a myectomy was completed.The pathologic specimen verified T1b grade 1 sprouting adenocarcinoma with 4350 µm invasion into the submucosa with negative resection margins.

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Sodium nitrite, a potent relaxant of rat stomach fundus: in vitro evidence

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y98-107 ◽

1998 ◽

Vol 76 (10-11) ◽

pp. 989-999 ◽

Cited By ~ 2

Author(s):

Michal Ceregrzyn ◽

Tsuyoshi Ozaki ◽

Atsukazu Kuwahara ◽

Maria Wiechetek

Keyword(s):

Methylene Blue ◽

Potassium Channels ◽

Guanylate Cyclase ◽

Sodium Nitrite ◽

Longitudinal Muscle ◽

Circular Muscle ◽

Muscle Layer ◽

Rat Stomach ◽

Longitudinal Muscle Layer ◽

Stomach Fundus

The effects of sodium nitrite (0.1, 1, 10 mM) on mechanical activity of isolated rat stomach fundus muscle and the influence of guanylate cyclase activity inhibitor (methylene blue) and channel inhibitors (tetrodotoxin, charybdotoxin, apamin) were studied. Nitrite evoked dose-dependent relaxation in the longitudinal and circular muscle layers. The lowest effective concentration of sodium nitrite was 0.1 mM, which is comparable with the NOAEL (no observed adverse effect level). Tetrodotoxin (1 µM) markedly inhibited electrically induced contraction and rebound relaxation, but did not influence the nitrite-induced relaxation. Charybdotoxin (100 nM) decreased the relaxation evoked by 10 mM nitrite to 52.3 and 65.7% of control reaction in the circular and longitudinal muscle layer, respectively. Apamin (100 nM) did not influence the nitrite-induced relaxation. Methylene blue (10 µM) decreased relaxation induced by nitrite in the longitudinal and circular muscle layer, respectively, to 66.7 and 54.3% of the response to 1 mM nitrite alone. Relaxation induced by nitrite was decreased in the presence of L-cysteine (5 mM), and in the circular and longitudinal muscle layer reached 29.6 and 23.1%, respectively, of the response to 1 mM nitrite alone. We conclude that the relaxing effect of nitrite on gastric fundus results from its direct action on smooth muscle cells and probably the enteric nervous system is not involved in this action. The nitrite-elicited relaxation depends on activation of guanylate cyclase and high conductance Ca2+-activated potassium channels; however, activation of potassium channels might be a part of or might act in parallel with the mechanism involving the cyclic GMP system. Effects of nitrite observed in the presence of L-cysteine suggest that nitrosothiols are not responsible for nitrite-evoked activation of guanylate cyclase.Key words: nitrite, gastric motility, tetrodotoxin, methylene blue, charybdotoxin, L-cysteine.

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Membrane currents recorded from a fragment of rabbit intestinal smooth muscle cell

AJP Cell Physiology ◽

10.1152/ajpcell.1986.251.3.c335 ◽

1986 ◽

Vol 251 (3) ◽

pp. C335-C346 ◽

Cited By ~ 63

Author(s):

Y. Ohya ◽

K. Terada ◽

K. Kitamura ◽

H. Kuriyama

Keyword(s):

Smooth Muscle ◽

Longitudinal Muscle ◽

Outward Current ◽

Ionic Currents ◽

Muscle Layer ◽

Dependent Manner ◽

Rabbit Ileum ◽

Longitudinal Muscle Layer ◽

Inward Current ◽

K Currents

Properties of ionic currents in smooth muscle membranes of the longitudinal muscle layer of the rabbit ileum were investigated using the single electrode voltage clamp method. In the present experiments, this method was applicable only to the smooth muscle ball (fragment) and not for the dispersed whole cell, because of incompleteness of the voltage clamping. A voltage step elicited a transient inward current followed by an outward current. This outward current was partly inhibited by Mn2+ or nisoldipine or by a reduction in the extracellular [Ca2+] ([Ca2+]o). Tetraethylammonium (TEA) reduced the delayed outward current in a dose-dependent manner, but 50 mM TEA did not produce a complete block of a residual current. When the pipette contained K+-free (Cs+ with TEA+) solution, the residual outward current was abolished. The inward current was elicited at -30 mV (holding potential of -60 mV) and reached the maximal value at +10 mV; the polarity was reversed at +60 mV. This inward current depended on the [Ca2+]o and was blocked by Mn2+ or nisoldipine. Ba2+ also permeated the membrane, and the inward current evoked by Ba2+ was also blocked by Mn2+ or nisoldipine. Reduction of [Na+]o in a solution containing 2.4 mM Ca2+ neither modified the current-voltage relation nor the decay of the inward current, but when [Ca2+]o was reduced to below 1 microM, Na+ permeated the membrane and was blocked by nisoldipine. In conclusion, ionic currents were recordable from the fragmented ball of the longitudinal muscle of rabbit ileum. There were at least two K+ currents as the outward current (Ca2+-dependent K+ and delayed K+ currents) and a Ca2+ current as the inward current. The property of the Ca2+ channel was similar to that observed with other preparations.

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Motility of the small intestine: a look ahead

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1985.248.5.g495 ◽

1985 ◽

Vol 248 (5) ◽

pp. G495-G500 ◽

Cited By ~ 4

Author(s):

J. R. Mathias ◽

C. A. Sninsky

Keyword(s):

Small Intestine ◽

Action Potential ◽

Muscle Layer ◽

Control Mechanisms ◽

Muscularis Mucosa ◽

Longitudinal Muscle Layer ◽

Look Ahead ◽

Health And Disease ◽

And Function ◽

Contraction And Relaxation

Motility of the gastrointestinal tract has become an important discipline of gastroenterology. In this paper we review important observations made during the early development of this discipline, note the current level of knowledge, and look ahead to some of the questions we believe will be addressed in the near future. Is the slow wave the action potential equivalent of the longitudinal muscle layer? How does the migrating action potential complex interrelate with the migrating myoelectric complex--are they two separate complexes under different control mechanisms? How do the myenteric plexus neurons relate to these complexes? Does the muscularis mucosa control the contraction and relaxation of the villous tips? Is there a finite area in the small intestine that can function as the pacemaker? How important are substances within the lumen in controlling motility? Finally, we emphasize the importance of structure and function of the plexus neurons in motility studies. We also stress the importance of collaboration and a multidisciplinary approach for future understanding of the mechanisms of the small intestine in health and disease.

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