Procedure for the histochemical demonstration of actomyosin ATPase.
About: This article is published in Experimental Neurology.The article was published on 1970-08-01. It has received 1014 citations till now.
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TL;DR: This chapter provides an overview of the principal features of perikaryal responses to axon injury and changes in axotomized neurons are generally assessed by comparison with the corresponding contralateral neurons of the experimental animal.
Abstract: Publisher Summary This chapter provides an overview of the principal features of perikaryal responses to axon injury. The neuron is an unusual cell. Its axon terminals may be situated at what in cellular terms is an enormous distance from the cell body (perikaryon); the volume of the latter may be but a small fraction of the total cellular volume. Yet the neuronal processes are maintained and their substance is constantly renewed from the perikaryon. The separation of an axon from its cell body results (in vertebrates) in the degeneration of the separated portion and is followed by a series of morphological changes in the perikarya. The most conspicuous of these is the disintegration, redistribution, and apparent disappearance from the cell body of cytoplasmic basophil material. Changes in axotomized neurons are generally assessed by comparison with the corresponding contralateral neurons of the experimental animal.
1,017 citations
TL;DR: It is demonstrated that type IID/X fibers make up a significant portion of the adult rat muscle mass and are intermediate to type IIA and IIB fibers in regard to fiber size and oxidative potential.
Abstract: A population of muscle fibers containing a myosin heavy-chain isoform IId (or 2x) has recently been identified in rat muscle. The purpose of this study was to histochemically determine the relative population and size of muscle fibers composed of type IID/X fibers as well as type I, IIA, and IIB fibers to estimate the absolute mass of the different types of fibers in rat muscle. In addition, muscle citrate synthase activity was measured to determine the relationship between fiber composition and muscle oxidative capacity. Seventy-six muscles or muscle parts from the face, neck, shoulder, arm, trunk, hip, thigh, and leg of three adult (4.5-5 mo of age) male Sprague-Dawley rats were removed, weighed, and frozen for histochemical and biochemical analyses. The data demonstrated that type IIB fibers make up 71% of the total muscle mass, type IID/X fibers 18%, type IIA fibers 5%, and type I fibers 6%. The mean cross-sectional area across all muscles was 5,078 +/- 175 microns 2 for type IIB fibers, 3,078 +/- 105 microns2 for type IID/X fibers, 2,045 +/- 80 microns2 for type IIA fibers, and 1,898 +/- 90 microns2 for type I fibers. Citrate synthase activity, an indicator of muscle mitochondrial content, was most closely related to the population of type IIA fibers and was in the rank order of type IIA > I > IID/X > IIB. NADH-tetrazolium reductase staining intensity also confirmed this order. These data demonstrate that type IID/X fibers make up a significant portion of the adult rat muscle mass and are intermediate to type IIA and IIB fibers in regard to fiber size and oxidative potential.
704 citations
TL;DR: A simple transition scheme has emerged from the multitude of data collected on fiber type conversions under a variety of conditions, and it is now clear that fiber type transitions do not proceed in immediate jumps from one extreme to the other, but occur in a graded and orderly sequential manner.
Abstract: Mammalian skeletal muscle is an extremely heterogeneous tissue, composed of a large variety of fiber types. These fibers, however, are not fixed units but represent highly versatile entities capable of responding to altered functional demands and a variety of signals by changing their phenotypic profiles. This adaptive responsiveness is the basis of fiber type transitions. The fiber population of a given muscle is in a dynamic state, constantly adjusting to the current conditions. The full range of adaptive ability spans fast to slow characteristics. However, it is now clear that fiber type transitions do not proceed in immediate jumps from one extreme to the other, but occur in a graded and orderly sequential manner. At the molecular level, the best examples of these stepwise transitions are myofibrillar protein isoform exchanges. For the myosin heavy chain, this entails a sequence going from the fastest (MHCIIb) to the slowest (MHCI) isoform, and vice-versa. Depending on the basal protein isoform profile and hence the position within the fast-slow spectrum, the adaptive ranges of different fibers vary. A simple transition scheme has emerged from the multitude of data collected on fiber type conversions under a variety of conditions.
651 citations
TL;DR: Even by using task-specific recruitment of the compartmentalized rat GM, additional endurance training interfered with the adaptive response of peak power training and attenuated the increase in maximal force after power training.
Abstract: Improvement of muscle peak power and oxidative capacity are generally presumed to be mutually exclusive. However, this may not be valid by using fibre type-specific recruitment. Since rat medial gastrocnemius muscle (GM) is composed of high and low oxidative compartments which are recruited task specifically, we hypothesised that the adaptive responses to peak power training were unaffected by additional endurance training. Thirty rats were subjected to either no training (control), peak power training (PT), or both peak power and endurance training (PET), which was performed on a treadmill 5 days per week for 6 weeks. Maximal running velocity increased 13.5% throughout the training and was similar in both training groups. Only after PT, GM maximal force was 10% higher than that of the control group. In the low oxidative compartment, mRNA levels of myostatin and MuRF-1 were higher after PT as compared to those of control and PET groups, respectively. Phospho-S6 ribosomal protein levels remained unchanged, suggesting that the elevated myostatin levels after PT did not inhibit mTOR signalling. In conclusion, even by using task-specific recruitment of the compartmentalized rat GM, additional endurance training interfered with the adaptive response of peak power training and attenuated the increase in maximal force after power training.
541 citations
Cites methods from "Procedure for the histochemical dem..."
...Following this, the 6-week training period started, during which the rats of the PT and PET group trained 5 days per week....
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TL;DR: This investigation characterized pure and hybrid fiber type distribution in 10 rat and 10 mouse skeletal muscles, as well as human vastus lateralis (VL) using multicolor immunofluorescence analysis, and determined fiber type-specific cross-sectional area (CSA), succinate dehydrogenase (SDH) activity, and α-glycerophosphate dehydrogenases (GPD) activity.
Abstract: Skeletal muscle is a heterogeneous tissue comprised of fibers with different morphological, functional, and metabolic properties. Different muscles contain varying proportions of fiber types; therefore, accurate identification is important. A number of histochemical methods are used to determine muscle fiber type; however, these techniques have several disadvantages. Immunofluorescence analysis is a sensitive method that allows for simultaneous evaluation of multiple MHC isoforms on a large number of fibers on a single cross-section, and offers a more precise means of identifying fiber types. In this investigation we characterized pure and hybrid fiber type distribution in 10 rat and 10 mouse skeletal muscles, as well as human vastus lateralis (VL) using multicolor immunofluorescence analysis. In addition, we determined fiber type-specific cross-sectional area (CSA), succinate dehydrogenase (SDH) activity, and α-glycerophosphate dehydrogenase (GPD) activity. Using this procedure we were able to easily identify pure and hybrid fiber populations in rat, mouse, and human muscle. Hybrid fibers were identified in all species and made up a significant portion of the total population in some rat and mouse muscles. For example, rat mixed gastrocnemius (MG) contained 12.2% hybrid fibers whereas mouse white tibialis anterior (WTA) contained 12.1% hybrid fibers. Collectively, we outline a simple and time-efficient method for determining MHC expression in skeletal muscle of multiple species. In addition, we provide a useful resource of the pure and hybrid fiber type distribution, fiber CSA, and relative fiber type-specific SDH and GPD activity in a number of rat and mouse muscles.
471 citations
References
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TL;DR: Higher phosphatase activity toward ATP and other substrates occurred at alkaline pH in thin (5 µ), unfixed, frozen sections incubated in the medium described by Gomori ('41) than when treated with the medium employed by Maengwyn-Davies et al ('52).
Abstract: Higher phosphatase activity toward ATP and other substrates occurred at alkaline pH in thin (5 µ), unfixed, frozen sections incubated in the medium described by Gomori ('41) than when treated with the medium employed by Maengwyn-Davies et al ('52). This difference in activities was caused principally by the salt content of the media. High sodium acetate concentration was strongly inhibitory to phosphatase activity toward adenosine triphosphate and α, β sodium glycerophosphateThe pH optimum of phosphatase activity of frozen sections toward adenosine triphosphate varied with the composition of the incubating medium. The localization of phosphatase activity toward adenosine triphosphate in cardiac muscle varied with substrate concentration, with nuclear staining becoming more prominent with increased adenosine triphosphate concentrations. The localization of phosphatase activity was not affected by the concentrations of α,β sodium glycerophosphate and adenosine-5-phosphate used, but the most rapid staining o...
662 citations
TL;DR: It is suggested that there are at least two qualitatively distinct actomyosin ATPases, and the nerve regulates the type of enzyme found in the muscle fiber, and preliminary observations indicate that under the influence of a foreign nerve, some acid-stabile fibers are converted to alkali- stabbed ones.
648 citations
TL;DR: Results from cross-reinnervation techniques are interpreted as indicating that regulation of gene expression is one of the “trophic” functions of the vertebrate neuron.
93 citations
TL;DR: Findings are presented that the ATPase of the high-activity (C) fibers is labile in acid (pH 4.35) and the ATP enzyme of the low- activity (B) fiber is labiles in alkali ( pH 10.4); these muscle fibers are phenotypically different with respect to their actomyosin ATPase.
64 citations