Sarcolemmal Invaginations Constituting the T System in Fish Muscle Fibers

Franzini‐Armstrong, Clara; Porter, Keith R.

doi:10.1083/jcb.22.3.675

Cited by 351 publications

(148 citation statements)

References 49 publications

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“…In addition, Huxley (1963) observed a thick filament diameter of 120 A in rabbit psoas muscle fixed in formaldehyde and negatively stained. It should be noted, however, that thick-filament diameters of 150 A have been reported in a fish muscle (Franzini-Armstrong and Porter, 1964). The thoracic muscle of the cockroach differs from some other insect flight muscles in that it appears to have longer and thicker myosin filaments and a larger ratio of thin to thick filaments.…”

Section: Discussionmentioning

confidence: 93%

The Filament Lattice of Cockroach Thoracic Muscle

Hagopian

Spiro

1968

The Journal of Cell Biology

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The fine structure of the tergo-coxal muscle of the cockroach, Leucophaea maderae, has been studied with the electron microscope. This muscle differs from some other types of insect flight muscles inasmuch as the ratio of thin to thick filaments is 4 instead of the characteristic 3. The cockroach flight muscle also differs from the cockroach femoral muscle in thin to thick filament ratios and diameters and in lengths of thick filaments. A comparison of these latter three parameters in a number of vertebrate and invertebrate muscles suggests in general that the diameters and lengths of the thick filaments and thin to thick filament ratios are related.

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Section: Discussionmentioning

confidence: 93%

The Filament Lattice of Cockroach Thoracic Muscle

Hagopian

Spiro

1968

The Journal of Cell Biology

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“…Los túbulos T son invaginaciones de la membrana plasmática que se extienden transversalmente en las fibras musculares y sirven como medio para llevar información eléctrica desde la superficie hasta el interior de la fibra muscular, particularmente hacia la membrana del retículo sarcoplásmico (16).…”

Section: El Mecanismo De Acoplamiento Excitación-contracción En El Múunclassified

“…Paralelamente, FranziniArmstrong y Porter estudiaron la tríada y el retículo sarcoplásmico mediante microscopía electrónica (16). Más tarde, otros autores como Weber, Hasselbach, Endo y Ebashi (5-9), mediante técnicas bioquímicas, permitieron reconocer la importancia del Ca 2+ en el acoplamiento excitación-contracción.…”

Section: Algunos Trabajos Experimentales Clásicosunclassified

“…Este estudio confirma algunos hallazgos obtenidos previamente por otros autores (16,23,24) y llama la atención sobre la existencia de algunas características estructurales nuevas: i) habría una estructura de unos 5 nm de ancho que subyace a la membrana interna del retículo sarcoplásmico, de naturaleza desconocida; ii) las partículas de calsequestrina parecen estar interconectadas entre sí dentro del retículo sarcoplásmico; iii) en la luz de las vesículas de túbulos T parecerían existir estructuras de naturaleza molecular desconocida que podrían tener un papel estructural; iv) se observa la presencia de estructuras que cubren las distancias entre la región citoplásmica del receptor de rianodina y el túbulo T, las cuales no pueden asignarse a un dominio proteico claro, pero podrían ser asas del receptor de dihidropiridinas. A pesar de las ventajas de esta técnica, los resultados presentados podrían afectarse por la inducción de artefactos durante el procesamiento de la muestra y por la baja resolución de las imágenes obtenidas.…”

Section: Estructura Y Acoplamiento Receptor De Dihidropiridinas-recepunclassified

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El acoplamiento excitación-contracción en el músculo esquelético: preguntas por responder a pesar de 50 años de estudio

Calderón-Vélez

Figueroa

2009

biomedica

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El mecanismo de acoplamiento excitación-contracción fue definido en el músculo esquelético como la secuencia de eventos que ocurre desde la generación del potencial de acción en la fibra muscular hasta que se inicia la generación de tensión. La regulación e interacción de dichos eventos entre sí ha sido estudiada durante los últimos 50 años utilizando diferentes técnicas, con las cuales se estableció la importancia y origen del ion calcio como activador contráctil, se conocen las principales proteínas involucradas y se inició el estudio de la base ultraestructural y de la regulación farmacológica; además, hay evidencias de que el acoplamiento excitación-contracción se altera en diferentes situaciones como en el envejecimiento, en la fatiga muscular y en algunas enfermedades musculares. Sin embargo, aún hay varias preguntas por responder: ¿cómo es el desarrollo y envejecimiento del mecanismo de acoplamiento excitación-contracción?, ¿cuál es su papel en la fatiga muscular y en algunas enfermedades musculares?, ¿cuál es la naturaleza de la interacción entre diferentes proteínas involucradas en el acoplamiento excitación-contracción? La presente revisión describe el acoplamiento excitación-contracción en el músculo esquelético y las técnicas utilizadas para su estudio como introducción para discutir algunas de las preguntas que aún falta por responder al respecto.Palabras clave: músculo esquelético, contracción muscular, relajación muscular, calcio, canal liberador de calcio, canales de calcio tipo L, receptor de rianodina, fatiga muscular. Excitation-contraction coupling in skeletal muscle: questions remaining after 50 years of researchThe excitation-contraction coupling mechanism was defined as the entire sequence of reactions linking excitation of plasma membrane to activation of contraction in skeletal muscle. By using different techniques, their regulation and interactions have been studied during the last 50 years, defining until now the importance and origin of the calcium ion as a contractile activator and the main proteins involved in the whole mechanism. Furthermore, the study of the ultrastructural basis and pharmacological regulation of the excitation-contraction coupling phenomenon has begun. The excitation-contraction coupling is thought to be altered in situations as ageing, muscle fatigue and some muscle diseases. However, many questions remain to be answered. For example, (1) How excitation-contraction coupling develops and ages? (2) What role does it play in muscle fatigue and other diseases? (3) What is the nature of the interaction between the proteins believed to be involved? The present review describes excitation-contraction coupling in skeletal muscle and techniques used to better understand it as an introduction for discussing unanswered questions regarding excitation-contraction coupling.

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“…There is growing reason to believe that in vertebrate skeletal muscles, as in the Ascaris muscle described here, the central component of the triad (the T system) is also nothing but a direct continuation of the plasma membrane (11,18). Its status as such has been uncertain because, like certain other plasma membrane invaginations, it has a tendency to disintegrate into chains of apparently intracytoplasmic vesicles after osmium tetroxide fixation (10).…”

Section: Plasma Membrane Infoldings and Sareoplasmic Reticulummentioning

confidence: 99%

ULTRASTRUCTURAL ORGANIZATION OF OBLIQUELY STRIATED MUSCLE FIBERS IN ASCARIS LUMBRICOIDES

Rosenbluth

1965

The Journal of Cell Biology

203

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The somatic musculature of the nematode, Ascaris, is currently thought to consist of smooth muscle fibers, which contain intracellular supporting fibrils arranged in a regular pattern. Electron microscopic examination shows that the muscle fibers are, in fact, comparable to the striated muscles of vertebrates in that they contain interdigitating arrays of thick and thin myofilaments which form H, A, and I bands. In the A bands each thick filament is surrounded by about l0 to 12 thin filaments. The earlier confusion about the classification of this muscle probably arose from the fact that in one longitudinal plane the myofilaments are markedly staggered and, as a result, the striations in that plane of section are not transverse but oblique, forming an angle of only about 6 ° with the filament axis. The apparent direction of the striations changes with the plane of the section and may vary all the way from radial to longitudinal. A three-dimensional model is proposed which accounts for the appearance of this muscle in various planes. Z lines as such are absent but are replaced by smaller, less orderly, counterpart "Z bundles" to which thin filaments attach. These bundles are closely associated with fibrillar dense bodies and with deep infoldings of the plasma membrane. The invaginations of the plasma membrane together with intracellular, flattened, membranous cisternae form dyads and triads. It is suggested that these complexes, which also occur at the cell surface, may constitute strategically located, low-impedance patches through which local currents are channeled selectively.

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Sarcolemmal Invaginations Constituting the T System in Fish Muscle Fibers

Cited by 351 publications

References 49 publications

The Filament Lattice of Cockroach Thoracic Muscle

The Filament Lattice of Cockroach Thoracic Muscle

El acoplamiento excitación-contracción en el músculo esquelético: preguntas por responder a pesar de 50 años de estudio

ULTRASTRUCTURAL ORGANIZATION OF OBLIQUELY STRIATED MUSCLE FIBERS IN ASCARIS LUMBRICOIDES

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