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James G Brasseur - One of the best experts on this subject based on the ideXlab platform.
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Muscle shortening along the normal esophagus during swallowing
Digestive Diseases and Sciences, 2006Co-Authors: Annapurna Korimilli, Vinod K Thangada, Chan Y Chung, James G Brasseur, Henry P. Parkman, Larry S. MillerAbstract:Longitudinal shortening of the esophagus during peristaltic contraction has been previously analyzed globally using spaced mucosal clips. This method gives a relatively crude measurement. In this study, local longitudinal shortening (LLS) was evaluated using simultaneous high-resolution endoluminal ultrasound (HREUS) and manometry based on basic principles of Muscle mechanics. We sought to determine if there are regional differences in LLS of the Esophageal Muscle during swallow-induced peristaltic contraction and evaluate shortening of the circular smooth Muscle (CSM) and longitudinal smooth Muscle (LSM) of the esophagus.
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a mathematical model for estimating Muscle tension in vivo during Esophageal bolus transport
Journal of Theoretical Biology, 2002Co-Authors: Mark A Nicosia, James G BrasseurAbstract:We present a model of Esophageal wall Muscle mechanics during bolus transport with which the active and "passive" components of circular Muscle tension are separately extracted from concurrent manometric and videofluoroscopic data. Local differential equations of motion are integrated across the Esophageal wall to yield global equations of equilibrium which relate total tension within the Esophageal wall to intraluminal pressure and wall geometry. To quantify the "passive" (i.e. inactive) length-tension relationships, the model equations are applied to a region of the esophagus in which active Muscle contraction is physiologically inhibited. Combining the global equations with space-time-resolved intraluminal pressure measured manometrically and videofluoroscopic geometry data, the passive model is used to separate active and "passive" components of Esophageal Muscle tension during bolus transport. The model is of general applicability to probe basic Muscle mechanics including the space-time stimulation of circular Muscle, the relationship between longitudinal Muscle tension and longitudinal Muscle shortening, and the contribution of the collagen matrix surrounding Muscle fibers to passive tension during normal human Esophageal bolus transport and in pathology. Example calculations of normal Esophageal function are given where active tone is found to extend only over a short intrabolus segment near the bolus tail and segmental regions of active Muscle squeeze are demonstrated.
Hirofumi Kuramoto - One of the best experts on this subject based on the ideXlab platform.
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contractile properties of Esophageal striated Muscle comparison with cardiac and skeletal Muscles in rats
BioMed Research International, 2010Co-Authors: Takahiko Shiina, Hirofumi Kuramoto, Takeshi Shima, Kazuaki Masuda, Haruko Hirayama, Momoe Iwami, Tadashi Takewaki, Yasutake ShimizuAbstract:The external Muscle layer of the mammalian esophagus consists of striated Muscles. We investigated the contractile properties of Esophageal striated Muscle by comparison with those of skeletal and cardiac Muscles. Electrical field stimulation with single pulses evoked twitch-like contractile responses in Esophageal Muscle, similar to those in skeletal Muscle in duration and similar to those in cardiac Muscle in amplitude. The contractions of Esophageal Muscle were not affected by an inhibitor of gap junctions. Contractile responses induced by high potassium or caffeine in Esophageal Muscle were analogous to those in skeletal Muscle. High-frequency stimulation induced a transient summation of contractions followed by sustained contractions with amplitudes similar to those of twitch-like contractions, although a large summation was observed in skeletal Muscle. The results demonstrate that Esophageal Muscle has properties similar but not identical to those of skeletal Muscle and that some specific properties may be beneficial for Esophageal peristalsis.
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galanin immunoreactive nerve terminals innervating the striated Muscle fibers of the rat esophagus
Neuroscience Letters, 1995Co-Authors: Hirofumi Kuramoto, Yasuhisa EndoAbstract:Abstract Galanin (GAL) immunohistochemistry combined with acetylcholinesterase (AChE) histochemistry was applied to demonstrate the innervation of the rat Esophageal Muscle coats. GAL immunoreactivity was found in a number of nerve cell bodies in the myenteric ganglia and in numerous varicose and non-varicose nerve fibers in the myenteric plexus and around blood vessels. Many GAL-positive varicose fibers ran in the internodal strands and along the striated Muscle fibers. They often ramified and terminated on the Muscle fibers to form arborizing structures, which were most abundant in the thoracic portion of the esophagus. Such GAL-positive terminals were localized in most (87.7%) of AChE-reactive motor endplates on the Esophageal striated Muscles. Left supranodose vagotomy caused a significant decrease of the GAL-arborizing terminals on the striated Muscles of the esophagus. This suggests that they are terminals of efferent fibers in the vagus nerve.
Boris Kablar - One of the best experts on this subject based on the ideXlab platform.
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evidence for the involvement of neurotrophins in Muscle transdifferentiation and acetylcholine receptor transformation in the esophagus of myf5 myod and nt 3 embryos
Developmental Dynamics, 2004Co-Authors: Tyler Reddy, Boris KablarAbstract:The primary aim of our study was to determine whether the Esophageal innervation (i.e., vagal and enteric) and the skeletal Muscle-secreted neurotrophins have a role in smooth-to-skeletal Muscle transdifferentiation and in the muscarinic-to-nicotinic acetylcholine receptor type transition. To that end, we used genetically engineered embryos and immunohistochemistry. We found that, in the absence of Myf5 and MyoD, the Esophageal Muscle cells failed to develop the striated phenotype of acetylcholine receptors. In addition, the development of vagal and enteric innervation was delayed in Myf5−/−:MyoD−/− and NT-3−/− mutants, but it was reestablished 2 days before the end of gestation. The smooth Muscle cells in the esophagus appeared to be a distinct subpopulation of cells and their ability to transdifferentiate was based on their competence to express neurotrophins and their receptors. Finally, our data suggest a role for NT-3 in the Esophageal Muscle transdifferentiation. Developmental Dynamics 231:683–692, 2004. © 2004 Wiley-Liss, Inc.
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Evidence for the involvement of neurotrophins in Muscle transdifferentiation and acetylcholine receptor transformation in the esophagus of Myf5(-/-):MyoD(-/-) and NT-3(-/-) embryos.
Developmental Dynamics, 2004Co-Authors: Tyler Reddy, Boris KablarAbstract:The primary aim of our study was to determine whether the Esophageal innervation (i.e., vagal and enteric) and the skeletal Muscle-secreted neurotrophins have a role in smooth-to-skeletal Muscle transdifferentiation and in the muscarinic-to-nicotinic acetylcholine receptor type transition. To that end, we used genetically engineered embryos and immunohistochemistry. We found that, in the absence of Myf5 and MyoD, the Esophageal Muscle cells failed to develop the striated phenotype of acetylcholine receptors. In addition, the development of vagal and enteric innervation was delayed in Myf5−/−:MyoD−/− and NT-3−/− mutants, but it was reestablished 2 days before the end of gestation. The smooth Muscle cells in the esophagus appeared to be a distinct subpopulation of cells and their ability to transdifferentiate was based on their competence to express neurotrophins and their receptors. Finally, our data suggest a role for NT-3 in the Esophageal Muscle transdifferentiation. Developmental Dynamics 231:683–692, 2004. © 2004 Wiley-Liss, Inc.
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Transdifferentiation of Esophageal smooth to skeletal Muscle is myogenic bHLH factor-dependent
Development (Cambridge England), 2000Co-Authors: Boris Kablar, Shahragim Tajbakhsh, Michael A. RudnickiAbstract:Previously, coexpression of smooth and skeletal differentiation markers, but not myogenic regulatory factors (MRFs), was observed from E16.5 mouse fetuses in a small percentage of diaphragm level Esophageal Muscle cells, suggesting that MRFs are not involved in the process of initiation of developmentally programmed transdifferentiation in the esophagus. To investigate smooth-to-skeletal Esophageal Muscle transition, we analyzed Myf5nlacZ knock-in mice, MyoD-lacZ and myogenin-lacZ transgenic embryos with a panel of the antibodies reactive with myogenic regulatory factors (MRFs) and smooth and skeletal Muscle markers. We observed that lacZ-expressing myogenic precursors were not detected in the esophagus before E15.5, arguing against the hypothesis that Muscle precursor cells populate the esophagus at an earlier stage of development. Rather, the expression of the MRFs initiated in smooth Muscle cells in the upper esophagus of E15.5 mouse embryos and was immediately followed by the expression of skeletal Muscle markers. Moreover, transdifferentiation was markedly delayed or absent only in the absence of Myf5, suggesting that appropriate initiation and progression of smooth-to-skeletal Muscle transdifferentiation is Myf5-dependent. Accordingly, the esophagus of Myf5(−/−):MyoD(−/−)embryos completely failed to undergo skeletal myogenesis and consisted entirely of smooth Muscle. Lastly, extensive proliferation of muscularis precursor cells, without programmed cell death, occurred concomitantly with Esophageal smooth-to-skeletal Muscle transdifferentiation. Taken together, these results indicate that transdifferentiation is the fate of all smooth Muscle cells in the upper esophagus and is normally initiated by Myf5.
Winfried Neuhuber - One of the best experts on this subject based on the ideXlab platform.
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enteric co innervation of striated Muscle fibers in the esophagus just a hangover
Anatomical Record-advances in Integrative Anatomy and Evolutionary Biology, 2001Co-Authors: Winfried Neuhuber, Ulrike Eichhorn, Jurgen WorlAbstract:Striated Muscle of the esophagus was until recently considered to consist of “classical” skeletal Muscle fibers innervated by cholinergic vagal motoneurons. The recently described co-innervation originating from enteric neurons expressing nNOS, VIP, NPY, and galanin added a new dimension of complexity. The aim of this study was to summarize current knowledge about, and to get further hints as to the possible function of enteric co-innervation of striated Esophageal Muscle fibers. Aldehyde fixed rat esophagi were processed for immunocytochemistry for CGRP or VAChT (to demonstrate vagal motor terminals), nNOS/NADPH-d, VIP, NPY, and galanin (to demonstrate enteric terminals), met-enkephalin, μ opiate receptor, muscarinic receptors m1-3, soluble guanylyl cyclase, and cGMP dependent kinase type I and II. Motor endplates were visualized using fluorochrome tagged α-bungarotoxin to label nicotinic receptors, or with AChE histochemistry. Besides light and confocal laser scanning microscopy, immuno electron microscopy was also employed. Up to 80% of motor endplates were co-innervated. In addition to nNOS, VIP, NPY, and galanin, many enteric terminals in Esophageal motor endplates expressed met-enkephalin. Some appeared to stain for the muscarinic m2 receptor. There was prominent immunostaining for the μ opioid receptor in the sarcolemma at both junctional and extrajunctional sites. Immunostaining for soluble guanylyl cyclase was prominent immediately beneath the clusters of nicotinic receptors. Enteric varicosities and vagal terminals intermingled in motor endplates often without intervening teloglial processes. During ontogeny, initially high co-innervation rates were reduced to adult levels in a cranio-caudally progressing manner. We conclude that, in addition to a possible nitrergic, VIP-, NPY-, and galaninergic modulation of neuromuscular transmission by enteric neurons, opioidergic mechanisms could play a role. On the other hand, cholinergic influence on enteric neurons may be exerted also by the nucleus ambiguus via motor endplates, in addition to the input from the dorsal motor nucleus. The observations that enteric nerve fibers contact striated Muscle fibers at specialized sites, i.e., motor endplates, and that these contacts appear in an ordered cranio-caudal sequence after cholinergic motor endplates have been established point to a specific function in neuronal control of Esophageal Muscle rather than to be an unspecific “hangover” from the smooth Muscle past of this organ. Anat Rec 262:41–46, 2001. © 2001 Wiley-Liss, Inc.
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spatial relationships of enteric nerve fibers to vagal motor terminals and the sarcolemma in motor endplates of the rat esophagus a confocal laser scanning and electron microscopic study
Cell and Tissue Research, 1996Co-Authors: Jurgen Worl, Bernd Mayer, Winfried NeuhuberAbstract:Enteric co-innervation of motor endplates in the rat esophagus was studied with confocal laser scanning and electron microscopy. Enteric fibers were demonstrated with immunocytochemistry for nitric oxide synthase, vasoactive intestinal peptide or NADPH-diaphorase histochemistry. Vagal motor terminals were identified with calcitonin gene-related peptide (CGRP) immunocytochemistry. Teloglia was stained with immuno- cytochemistry for S100, and TRITC-tagged α-bungarotoxin was used to delineate endplate areas in immmunofluorescence preparations. Both confocal imaging and electron microscopy revealed intimate relationships between enteric and vagal terminals on the one hand, and enteric terminals and the sarcolemma on the other. In addition, electron microscopy could point out direct apposition of a significant proportion of enteric varicosities to vagal motor terminals without intervening teloglial processes. These morphological data are compatible with pre- and postsynaptic modulatory effects of enteric neurons on vagal neuromuscular transmission in striated Esophageal Muscle.
Yasuhisa Endo - One of the best experts on this subject based on the ideXlab platform.
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galanin immunoreactive nerve terminals innervating the striated Muscle fibers of the rat esophagus
Neuroscience Letters, 1995Co-Authors: Hirofumi Kuramoto, Yasuhisa EndoAbstract:Abstract Galanin (GAL) immunohistochemistry combined with acetylcholinesterase (AChE) histochemistry was applied to demonstrate the innervation of the rat Esophageal Muscle coats. GAL immunoreactivity was found in a number of nerve cell bodies in the myenteric ganglia and in numerous varicose and non-varicose nerve fibers in the myenteric plexus and around blood vessels. Many GAL-positive varicose fibers ran in the internodal strands and along the striated Muscle fibers. They often ramified and terminated on the Muscle fibers to form arborizing structures, which were most abundant in the thoracic portion of the esophagus. Such GAL-positive terminals were localized in most (87.7%) of AChE-reactive motor endplates on the Esophageal striated Muscles. Left supranodose vagotomy caused a significant decrease of the GAL-arborizing terminals on the striated Muscles of the esophagus. This suggests that they are terminals of efferent fibers in the vagus nerve.