scholarly journals THE STRIATED MUSCULATURE OF BLOOD VESSELS

1960 ◽  
Vol 8 (1) ◽  
pp. 135-150 ◽  
Author(s):  
H. E. Karrer
Keyword(s):  
Plasma Membrane ◽  
Plasma Membranes ◽  
Striated Muscle ◽  
Muscle Cells ◽  
Free Cell ◽  
Uranyl Acetate ◽  
Dense Layer ◽  
Intercalated Discs ◽  
Lateral Cell ◽  
Conduction Of Excitation

The interconnections and the surfaces of the striated muscle cells which occur in thoracic and in lung veins of the mouse were studied with the electron microscope. The osmium-fixed tissues were embedded in methacrylate or in araldite and sectioned with a Porter-Blum microtome. Many preparations were stained before embedding with phosphotungstic acid or after sectioning with uranyl acetate. Typical intercalated discs are observed in this muscle. They are similar to the discs found in heart muscle. These intercalated discs represent boundaries between separate muscle cells. Along the discs, cells are joined in planes normal to their myofilaments. The same cells are also joined in planes parallel to the myofilaments by means of lateral interconnections. These lateral cell boundaries are in continuity with the intercalated discs. Three morphologically distinct parts occur within the lateral cell interconnections: One is characterized by small vesicles along the plasma membrane, the second part has the structure of desmosomes, and a third part represents an external compound membrane (formed by the two plasma membranes of the adjoining cells) and is termed "quintuple-layered cell interconnection." Small vesicles and plasma membrane enfoldings along the free surface of muscle cells are interpreted as products of a pinocytosis (phagocytosis) process. Some of them are seen to contain small membrane-bounded bodies or granules. The free cell surface shows a characteristic outer dense layer ("basement membrane") which accompanies the plasma membrane. The topographic relation of this dense layer with the plasma membrane seems to vary in different preparations. The significance of this variation is not well understood. On two occasions a typical arrangement o vesicles and tubules was observed at Z band levels, just beneath the plasma membrane. These structures are believed to represent endoplasmic reticulum. Their possible significance for the conduction of excitation is discussed.

scholarly journals Electron Microscopy of Peripheral Nerves and Neuromuscular Junctions in the Wasp Leg

1958 ◽  
Vol 4 (1) ◽  
pp. 107-114 ◽  
Author(s):  
George A. Edwards ◽  
Helmut Ruska ◽  
Étienne de Harven
Keyword(s):  
Plasma Membrane ◽  
Peripheral Nerve ◽  
Muscle Fiber ◽  
Plasma Membranes ◽  
Striated Muscle ◽  
Neuromuscular Junctions ◽  
Basement Membranes ◽  
Nerve Branch ◽  
Yellow Jacket ◽  
Peripheral Axon

The peripheral nerve branch innervating the femoral muscles of the common yellow jacket (Vespula carolina) has been found to possess a thick lemnoblast basement membrane and a complex mesaxon. The term "tunicated nerve" is proposed to designate the type of peripheral nerve in which one or several axons are loosely mantled by meandering, cytoplasm-enclosing membranes of the lemnoblast. The peripheral axon courses longitudinally in a groove in the muscle fiber between the plasma membrane of the muscle fiber and a cap formed by lemnoblast and tracheoblast. The junction is characterized by apposition of plasma membranes of axon and muscle fiber, abundant mitochondria, and synaptic vesicles in the axon, and aggregates of "aposynaptic granules" plus mitochondria and endoplasmic reticulum on the muscle side of the synapse. Unlike the vertebrate striated muscle fiber, no complex infolding of the synapsing plasma membrane of the muscle fiber occurs. The "connecting tissue" of the insect is formed by tracheoblasts, their basement membranes, and the basement membranes of other cells. Further mechanical support is given by the ramifying tracheoles. The physiologic roles of the specialized structures are considered.

scholarly journals Ultrastructure of developing human muscle: the problem of multinucleation of striated muscle cells

1986 ◽  
Vol 44 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Guilberto Minguetti ◽  
W. G. P. Mair
Keyword(s):  
Electron Microscopy ◽  
Basement Membrane ◽  
Plasma Membranes ◽  
Striated Muscle ◽  
Muscle Cells ◽  
Human Muscle ◽  
Membrane Tube ◽  
Embryonic Myogenesis ◽  
Human Foetuses

The authors studied by electron microscopy the muscle of 27 human foetuses ranging from 9 weeks to 9 months development. It was possible to observe that disintegration of the plasma membranes of adjacent myoblasts and myotubes which share a common basement membrane tube appears to occur in longitudinally disposed cells of those categories. This may help to explain how further nuclei may be incorporated into well developed myotubes and how the striated muscle cells become multinucleated during embryonic myogenesis and regeneration in vivo.

A comparison of membrane fracture faces of fixed and unfixed glycerinated tissue

1976 ◽  
Vol 21 (3) ◽  
pp. 437-448
Author(s):  
A.S. Breathnach ◽  
M. Gross ◽  
B. Martin ◽  
C. Stolinski
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Plasma Membranes ◽  
Striated Muscle ◽  
Freeze Fracture ◽  
Particle Aggregation ◽  
Buccal Epithelium ◽  
Mitochondrial Membranes ◽  
Nuclear Membranes ◽  
General Plasma

Fixed (glutaraldehyde, 3%) and unfixed specimens of rat buccal epithelium, striated muscle, and liver, were cryoprotected with glycerol, freeze-fractured, and replicated without sublimation. A comparison of fracture faces of general plasma membranes, nuclear membranes, mitochondrial membranes, and membranes of rough endoplasmic reticulum revealed no significant differences as between fixed and unfixed material. Apart from some membranes of liver endoplasmic reticulum, there was no evidence of aggregation or redistribution of intramembranous particles in the unfixed material. The results demonstrate that chemical prefixation of tissues for freeze-fracture is not always necessary, or even desirable, and that glycerol may not be as deeply or directly implicated in particle aggregation as previously thought. Fixation with glutaraldehyde alters the cleaving behaviour of plasma membrane at desmosomes and tight junctions, but not at gap junctions.

Rapid stimulation of glucose transport by mitochondrial uncoupling depends in part on cytosolic Ca2+ and cPKC

1998 ◽  
Vol 275 (6) ◽  
pp. C1487-C1497 ◽  
Author(s):  
Zayna A. Khayat ◽  
Theodoros Tsakiridis ◽  
Atsunori Ueyama ◽  
Romel Somwar ◽  
Yousuke Ebina ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Protein Kinase ◽  
Glucose Uptake ◽  
Glucose Transport ◽  
Energy Demand ◽  
Plasma Membranes ◽  
Muscle Cells ◽  
Atp Production ◽  
Pkc Β ◽  
Stimulation Of

2,4-Dinitrophenol (DNP) uncouples the mitochondrial oxidative chain from ATP production, preventing oxidative metabolism. The consequent increase in energy demand is, however, contested by cells increasing glucose uptake to produce ATP via glycolysis. In L6 skeletal muscle cells, DNP rapidly doubles glucose transport, reminiscent of the effect of insulin. However, glucose transport stimulation by DNP does not require insulin receptor substrate-1 phosphorylation and is wortmannin insensitive. We report here that, unlike insulin, DNP does not activate phosphatidylinositol 3-kinase, protein kinase B/Akt, or p70 S6 kinase. However, chelation of intra- and extracellular Ca2+ with 1,2-bis(2-aminophenoxy)ethane- N, N, N′, N′-tetraacetic acid-AM in conjunction with EGTA inhibited DNP-stimulated glucose uptake by 78.9 ± 3.5%. Because Ca2+-sensitive, conventional protein kinase C (cPKC) can activate glucose transport in L6 muscle cells, we examined whether cPKC may be translocated and activated in response to DNP in L6 myotubes. Acute DNP treatment led to translocation of cPKCs to plasma membrane. cPKC immunoprecipitated from plasma membranes exhibited a twofold increase in kinase activity in response to DNP. Overnight treatment with 4-phorbol 12-myristate 13-acetate downregulated cPKC isoforms α, β, and γ and partially inhibited (45.0 ± 3.6%) DNP- but not insulin-stimulated glucose uptake. Consistent with this, the PKC inhibitor bisindolylmaleimide I blocked PKC enzyme activity at the plasma membrane (100%) and inhibited DNP-stimulated 2-[3H]deoxyglucose uptake (61.2 ± 2.4%) with no effect on the stimulation of glucose transport by insulin. Finally, the selective PKC-β inhibitor LY-379196 partially inhibited DNP effects on glucose uptake (66.7 ± 1.6%). The results suggest interfering with mitochondrial ATP production acts on a signal transduction pathway independent from that of insulin and partly mediated by Ca2+ and cPKCs, of which PKC-β likely plays a significant role.

scholarly journals A CHOLINERGIC COMPONENT IN THE INNERVATION OF THE LONGITUDINAL SMOOTH MUSCLE OF THE GUINEA PIG VAS DEFERENS

1969 ◽  
Vol 41 (2) ◽  
pp. 462-476 ◽  
Author(s):  
Peter M. Robinson
Keyword(s):  
Smooth Muscle ◽  
Plasma Membrane ◽  
Guinea Pig ◽  
Smooth Muscle Cells ◽  
Plasma Membranes ◽  
Vas Deferens ◽  
Muscle Cells ◽  
Muscle Membrane ◽  
Smooth Muscle Tissue ◽  
Longitudinal Smooth Muscle

Acetylcholinesterase (AChE) has been detected on the plasma membrane of about 25% of the axons in the longitudinal smooth muscle tissue of guinea pig vas deferens. These axons are presumably cholinergic. No enzyme was detected in the remaining 75% of axons. These axons are presumably adrenergic. The plasma membrane of the Schwann cells associated with the cholinergic axons also stained for AChE. Some axon bundles contained only cholinergic or adrenergic axons while others contained both types of axon. When a cholinergic axon approached within 1100 A of a smooth muscle cell, there was a patch of AChE activity on the muscle membrane adjacent to the axon. It is suggested that these approaches are the points of effective transmission from cholinergic axons to smooth muscle cells. Butyrylcholinesterase activity was detected on the plasma membranes of all axons and smooth muscle cells in this tissue.

scholarly journals THE ULTRASTRUCTURAL LOCALIZATION OF THE ISOZYMES OF ASPARTATE AMINOTRANSFERASE IN MURINE TISSUES

1970 ◽  
Vol 47 (1) ◽  
pp. 84-98 ◽  
Author(s):  
J. M. Papadimitriou ◽  
P. Van Duijn
Keyword(s):  
Plasma Membrane ◽  
Enzymatic Activity ◽  
Aspartic Acid ◽  
Aspartate Aminotransferase ◽  
Plasma Membranes ◽  
Striated Muscle ◽  
Lead Nitrate ◽  
Lead Salt ◽  
Ground Substance ◽  
Transverse Tubular System

Two isozymes of aspartate aminotransferase have been demonstrated biochemically. One isozyme is found in the mitochondrial fraction of the cytoplasm, the other ("soluble") in the supernatant. Both isozymes can be demonstrated by the cytochemical technique of Lee and Torack, as reported in the preceding report. Aldehyde fixation rapidly inactivates both isozymes, especially the soluble one. Inactivation can be delayed by addition of ketoglutarate to the fixative. The ketoglutarate probably competes with the fixative for the active site of the enzyme, thus protecting that region of the molecule. This enables adequate tissue preservation with enough remaining enzymatic activity to be demonstrated by the precipitation of oxaloacetate as the lead salt from a medium containing α-ketoglutaric acid aspartic acid, and lead nitrate. Electron-opaque material was found not only in mitochondria but, as the result of substrate protection, on the plasma membranes of many cells including erythrocytes and bacteria, the limiting membrane of peroxisomes, and the transverse tubular system of striated muscle. Occasional centrioles, neurotubules, tubules in the tails of spermatozoa, the A-I band junction in myofibrils of striated muscle, and the ground substance between cisternae of endoplasmic reticulum in intestinal goblet cells also showed precipitate. In all cases, replacement of L-aspartic acid by D-aspartic acid in the medium resulted in unstained sections. The sensitivity of extramitochondrial sites to fixation, the need of ketoglutarate as an agent for protecting the enzymatic activity during the fixation process, and the known presence of only soluble isozyme in erythrocytes indicate that enzymatic activity at these sites can be attributed to the soluble isozyme. Localization of the soluble isozyme on the plasma membrane may be related to possible involvement in depolarization phenomena, amino acid transport, or synthesis of plasma membrane-bound mucopolysaccharides.

Myogenesis of normal and dystrophic chick embryonic skeletal muscle cells in vitro: biosynthesis of plasma membrane proteins

1980 ◽  
Vol 58 (10) ◽  
pp. 1156-1164 ◽  
Author(s):  
Paul C. Holland ◽  
George A. Cates ◽  
Byron S. Wenger ◽  
Barbara L. Raney
Keyword(s):  
Skeletal Muscle ◽  
Plasma Membrane ◽  
Membrane Proteins ◽  
Plasma Membranes ◽  
Protein Biosynthesis ◽  
Sodium Dodecyl ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Plasma Membrane Proteins ◽  
Dystrophic Muscle

Plasma membranes were prepared from primary cell cultures of normal and genetically dystrophic chick embryonic pectoral muscle. These membranes were analyzed both by one-dimensional sodium dodecyl sulphate – polyacrylamide slab gel electrophoresis and by two-dimensional electrophoresis using isoelectric focusing in the first dimension. No marked and reproducible abnormalities could be detected in the synthesis, or accumulation, of plasma membrane proteins of dystrophic muscle cells maintained in culture for periods of up to 6 days. Analysis of the relative rates of protein turnover, analysis of fucose incorporation into plasma membrane proteins, and comparison of iodinated cell surface proteins also failed to reveal distinct abnormalities in plasma membranes derived from cultured dystrophic muscle cells. Although the results obtained do not rule out an early defect in plasma membrane protein biosynthesis during the development of dystrophic skeletal muscle in vivo, they do demonstrate that the synthesis and assembly of at least the major plasma membrane proteins occur normally during the initial phases of terminal differentiation of isolated dystrophic skeletal muscle cells in tissue culture.

scholarly journals ARCHITECTURE AND NERVE SUPPLY OF MAMMALIAN SMOOTH MUSCLE TISSUE

1957 ◽  
Vol 3 (6) ◽  
pp. 867-878 ◽  
Author(s):  
Rudolf Caesar ◽  
George A. Edwards ◽  
Helmut Ruska
Keyword(s):  
Endoplasmic Reticulum ◽  
Smooth Muscle ◽  
Plasma Membrane ◽  
Smooth Muscle Cells ◽  
Muscle Cell ◽  
Muscle Tissue ◽  
Plasma Membranes ◽  
Muscle Cells ◽  
Autonomic Nerves ◽  
Smooth Muscle Tissue

Smooth muscle tissue from mouse urinary bladder, uterus, and gall bladder has been studied by means of the electron microscope. The smooth muscle cells are distinctly and completely separated from each other by a cytolemma comparable to the sarcolemma of striated muscle. The tissue is thus cellular and not syncytial. With this evidence, supported by electron microscopy of other tissues, we question the existence of true syncytia in animal tissues. Individual cell membranes necessary for the electrophysiologic events exist in smooth muscle, and its nerve and conduction in a tissue such as uterus or bladder can occur at the cellular level as well as at the tissue area level. The smooth muscle cell contains myofilaments, nucleus, endoplasmic reticulum, mitochondria, Golgi complex, centrosome, and pinocytotic vesicles. These structures are described in some detail, and their probable interrelations and functions are discussed. The autonomic nerves innervating smooth muscle cells are composed of axons and lemnoblasts. The axon is suspended by the mesaxon formed by the infolded plasma membrane of the lemnoblast. The respective plasma membranes separate axon and lemnoblast from each other and from surrounding muscle cells. The axons of autonomic nerves never penetrate the plasma membrane of the muscle cell, but pass or intrude into muscle cell pockets, forming a contact between axonal plasma membrane and smooth muscle plasma membrane. The lemnoblast shows well developed endoplasmic reticulum with Palade granules, mitochondria, and a long, elliptical nucleus. The axon contains neurofilaments, mitochondria, and synaptic vesicles; the quantity of the latter two being significantly greater in the periphery of lemnoblasts and near axon-muscle contact regions. We regard the contact regions as the synapses between the autonomic nerves and the smooth muscle cells.

Specialized Junctions of the Intercalated Disc of the Active and Hibernating Bat Heart

1972 ◽  
Vol 30 ◽  
pp. 26-27
Author(s):  
Martin Hagopian
Keyword(s):  
Osmium Tetroxide ◽  
Natural Habitat ◽  
Muscle Cells ◽  
Uranyl Acetate ◽  
Myotis Lucifugus ◽  
Intercalated Disc ◽  
En Bloc ◽  
Intercalated Discs ◽  
End To End

Active bats, Myotis lucifugus, were caught in October, and hibernating bats were caught in January from their natural habitat. Left ventricles were fixed in 6.25% cacodylate buffered gluturaldehyde, washed in buffer, and postfixed in 1% osmium tetroxide. Some tissue in each group was stained en bloc with uranyl acetate, dehydrated, and embedded in Araldite or Epon.The muscle cells of the bat heart are approximately cylindrical in shape and are connected with one another end-to-end at the intercalated discs. Occasionally the cardiocytes are connected along the lateral surfaces. In general the intercalated disc is composed of transverse and longitudinal segments.

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