Galanin induces contraction of isolated cells from circular muscle layer of pig ileum

1991 ◽  
Vol 32 (3) ◽  
pp. 369-374 ◽  
Author(s):  
Michel Delvaux ◽  
Alain Botella ◽  
Jean Fioramonti ◽  
Jacques Frexinos ◽  
Lionel Bueno
Keyword(s):  
Circular Muscle ◽  
Muscle Layer ◽  
Isolated Cells ◽  
Circular Muscle Layer

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

2017 ◽  
Vol 05 (03) ◽  
pp. E146-E150 ◽  
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.

scholarly journals The transwall gradient across the mouse colonic circular muscle layer is carbon monoxide dependent

2010 ◽  
Vol 24 (10) ◽  
pp. 3840-3849 ◽  
Author(s):  
L. Sha ◽  
G. Farrugia ◽  
D. R. Linden ◽  
J. H. Szurszewski
Keyword(s):  
Carbon Monoxide ◽  
Circular Muscle ◽  
Muscle Layer ◽  
Circular Muscle Layer

Correlation between electrical and morphological properties of canine pyloric circular muscle

1991 ◽  
Vol 260 (3) ◽  
pp. G390-G398 ◽  
Author(s):  
F. Vogalis ◽  
S. M. Ward ◽  
K. M. Sanders
Keyword(s):  
Single Cells ◽  
Electrical Coupling ◽  
Circular Muscle ◽  
Muscle Layer ◽  
Morphological Properties ◽  
Morphological Examination ◽  
Isolated Cells ◽  
Time Constants ◽  
Morphological Studies ◽  
Cable Properties

Electrical slow waves decay in amplitude as they conduct from the myenteric to the submucosal regions of the circular muscle layer in the canine pyloric sphincter. We used the partitioned chamber method to study the passive and active properties of pyloric muscles, and we found that length constants of circular muscles of myenteric region were significantly longer than muscles near the submucosal surface. These data suggested differences in either membrane resistance, junctional resistance, or cytoplasmic resistance. The first parameter was evaluated by measuring time constants in intact tissues and single cells isolated from the submucosal and myenteric regions. Membrane time constants were not different in the two regions, nor were differences found in the input resistances of isolated cells. Morphological studies failed to demonstrate differences in cell diameters in the two regions suggesting that cytoplasmic resistances are similar. These findings suggest that the different cable properties in the two regions may be due to differences in electrical coupling. Morphological examination revealed similar numbers of gap junctions between cells in the two regions, but large differences were noted in the size of muscular bundles. Muscles of the myenteric region were arranged into large, tightly packed bundles, whereas muscles of the submucosal region consisted of small bundles with an extensive extracellular space filled with connective tissue. We suggest that the difference in cable properties may be due to differences in electrical coupling between bundles. These data suggest that submucosal muscles function more like a multiunit smooth muscle, whereas myenteric muscles behave as a single unit.

Cholinergic nerve-mediated excitation in the guinea pig choledochoduodenal junction activated by distension

1994 ◽  
Vol 267 (5) ◽  
pp. G938-G946 ◽  
Author(s):  
F. Vogalis ◽  
R. R. Bywater ◽  
G. S. Taylor
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Action Potential ◽  
Action Potentials ◽  
Discharge Rate ◽  
Circular Muscle ◽  
Muscle Layer ◽  
Circular Muscle Layer ◽  
Circular Layer ◽  
Longitudinal Layer

The electrical basis of propulsive contractions in the guinea pig choledochoduodenal junction (CDJ), which are triggered by distension, was investigated using intracellular microelectrode recording techniques. The isolated CDJ was placed in a continuously perfused tissue chamber at 37 degrees C. Membrane potential was recorded from smooth muscle cells in either the ampulla or in the upper CDJ (upper junction) regions, which were immobilized by pinning. Distension of the upper junction (20-30 s) by increasing intraductal hydrostatic pressure (mean elevation: 2.0 +/- 0.3 kPa, n = 13) triggered "transient depolarizations" (TDs: < 5 mV in amplitude and 2-5 s in duration) and action potentials in the circular muscle layer of the ampulla. The frequency of TDs in the ampulla was increased from 2.2 +/- 0.2 to 15.9 +/- 2.2 min-1 (n = 13) during distension. Simultaneous impalements of cells in the longitudinal and circular muscle layers in the ampulla revealed that subthreshold TDs in the circular layer were associated with an increased rate of action potential discharge in the longitudinal layer. Atropine (Atr; 1.4 x 10(-6) M) and tetrodotoxin (TTX; 3.1 x 10(-6) M blocked the distension-evoked increase in TD frequency, without affecting the frequency of ongoing TDs. The sulfated octapeptide of cholecystokinin (1-5 x 10(-8) M) increased the amplitude of TDs recorded in the circular muscle layer of the ampulla and increased action potential discharge rate. In separate recordings, radial stretch of the ampulla region increased the rate of discharge of action potentials in the smooth muscle of the upper junction.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of transmural field stimulation in isolated muscle strips from human esophagus

1990 ◽  
Vol 258 (3) ◽  
pp. G344-G351 ◽  
Author(s):  
A. Tottrup ◽  
A. Forman ◽  
P. Funch-Jensen ◽  
U. Raundahl ◽  
K. E. Andersson
Keyword(s):  
Longitudinal Muscle ◽  
Circular Muscle ◽  
Muscle Layer ◽  
Isometric Tension ◽  
Field Stimulation ◽  
Platinum Electrodes ◽  
Longitudinal Muscle Layer ◽  
Circular Muscle Layer ◽  
Human Esophagus ◽  
40 Hz

Smooth muscle strips representing longitudinal and circular muscle layers of the esophagogastric junction (EGJ) and esophageal body (EB) of the human esophagus were prepared. The strips were mounted in organ baths and isometric tension was recorded. Square wave stimulation was applied through platinum electrodes. Only responses abolished by tetrodotoxin (TTX) were considered neurogenic. Strips taken from longitudinal muscle layers of the EB and EGJ contracted during field stimulation. The responses evoked were abolished by atropine, and optimal frequency of stimulation was 40 Hz. In strips taken from the circular muscle layer of the EB, a contraction occurred after cessation of the stimulus. Atropine inhibited 90% of this response; the optimal stimulation frequency was 40 Hz. When a tone was induced in strips from this layer, a TTX-sensitive relaxation was seen during field stimulation. During stimulation of strips from the EGJ circular muscle layer, which was the only preparation developing spontaneous active tone, a relaxation was seen. A small contraction followed after termination of the stimulus. The relaxation, which was nonadrenergic, noncholinergic, reached maximum at 10 Hz. Atropine inhibited 40% of the contraction. The results suggest that in the longitudinal muscle layer of the human lower esophagus field stimulation causes postganglionic nerves to release transmitter(s) acting on muscarinic receptors. The responses of circular muscle layers seem to be mediated through release of at least two transmitters.

Electrical coupling in the circular muscles of dog jejunum

1979 ◽  
Vol 57 (6) ◽  
pp. 578-580 ◽  
Author(s):  
Elane Zelcer ◽  
E. E. Daniel
Keyword(s):  
Gap Junctions ◽  
Electrical Coupling ◽  
Circular Muscle ◽  
Muscle Layer ◽  
Dense Layer ◽  
Isolated Cells ◽  
Alternate Pathway ◽  
Significant Difference ◽  
Circular Layer ◽  
Passive Current

Two distinct layers of circular muscle have previously been demonstrated in dog jejunum, the main circular layer containing many gap junction contacts, and an inner dense muscle layer where no gap junctions have been found. Length constants were determined for these muscle layers and no significant difference was found between these values. The main circular muscle cells had lower membrane potentials and may have had abnormally low space constants owing to injury. It was concluded that the absence of gap junctions in the inner dense layer does not reduce the spread of passive current as might be expected of electrically isolated cells, and it is suggested that an alternate pathway for passive current exists in this layer.

scholarly journals Neonatal administration of tamoxifen causes disruption of myometrial development but not adenomyosis in the C57/BL6J mouse

Reproduction ◽  
2010 ◽  
Vol 139 (6) ◽  
pp. 1067-1075 ◽  
Author(s):  
Mohamed K Mehasseb ◽  
S C Bell ◽  
M A Habiba
Keyword(s):  
Smooth Muscle Actin ◽  
Circular Muscle ◽  
Muscle Layer ◽  
Abnormal Development ◽  
Circular Muscle Layer ◽  
Receptor Modulation ◽  
Age Related ◽  
Uterine Adenomyosis ◽  
Development And Differentiation ◽  
Neonatal Administration

We previously demonstrated that in the CD-1 mouse, which exhibits a high incidence of age-related adenomyosis, neonatal exposure to tamoxifen induced premature uterine adenomyosis and was associated with abnormal development particularly of the inner myometrium. In the present study, we examined the effect of neonatal tamoxifen administration upon uterine development in the C57/BL6J mouse strain that is not known to develop uterine adenomyosis. Female C57/BL6J pups (n=20) were treated with oral tamoxifen (1 mg/kg) from age 1 to 5 days. Uteri from control and treated mice were obtained on days 5, 10, 15 and 42 of age. We examined sections histologically using image analysis and immunohistochemistry for α-smooth muscle actin (ACTA2, α-SMA), desmin, vimentin, laminin, fibronectin and oestrogen receptor-α (ESR1). Following tamoxifen exposure, all uteri showed inner myometrium thinning, lack of continuity, disorganisation and bundling. However, adenomyosis was not seen in any uterus. ACTA2 immunostaining was less in the circular muscle layer of treated mice. The temporal pattern of desmin immunostaining found in control mice was absent in tamoxifen-treated mice. There was no difference in the localisation of laminin or fibronectin between control and tamoxifen-treated groups. However, laminin immunostaining was reduced in the circular muscle layer of treated mice. Vimentin could not be detected in either group. In conclusion, our results demonstrate that the development of the inner myometrium is particularly sensitive to oestrogen antagonism, and is affected by steroid receptor modulation. Although tamoxifen induces inner myometrial changes including that of ACTA2, desmin, ESR1 and laminin expression in C57/BL6J neonatal mice similar to those induced in CD-1 mice, C57/BL6J mice did not develop premature adenomyosis. Thus, disruption of the development and differentiation of the inner myometrium cannot alone explain the development of tamoxifen-associated adenomyosis, and this must be dependent upon its interaction with strain-dependent factors.

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