Histochemical and immunohistochemical profile of pink muscle fibres in some teleosts

Summary The pink muscle of several Teleosts was examined immunohistochemically using antisera specific for the myosins of red and white muscle, and histochemically using various methods for demonstrating myosin ATPase (in ATPase) activity.In the catfish the pink muscle consists of 2 different layers of fibres. The superficial layer has a low mATPase activity after both acid and alkali pre-incubation, whereas the deeper layer has a high mATPase activity after acid and alkali pre-incubation, being more resistent to these conditions even than is the white muscle.In the trout the pink muscle is composed of fibres with the same mATPase activity as in the superficial pink muscle of the catfish, whereas in the rock goby, goldfish, mullet and guppy the pink muscle is like the deep pink layer of the catfish.Immunohistochemically the fibres of the pink muscle behave like the white muscle fibres except in the guppy and rock goby in which at the level of the lateral line there occurs a transition zone between red and pink fibres. The fibres of this region react with both anti-fast and (to a lesser extent) anti-slow myosin antisera, and have a mATPase activity which, going from the superficial to the deeper fibres, gradually loses the red muscle characteristics to acquire those of the main pink muscle layer.     

Histochemical and immunohistochemical properties of skeletal muscle fibres fromRana andXenopus

Summary Modern histochemical and immunohistochemical techniques have been used to type skeletal muscle fibres from threeRana species andXenopus laevis.Differing myosin properties and metabolic capacities (representing various contractile properties) define a minimum of four fibre types inRana and five inXenopus. TheRana andXenopus types are sufficiently similar so that a single nomencclature can be applied to them. This nomenclature uses an initial letter indicating the probable contractile performance (F=fast-twitch, S=slow-twitch and T=tonic), and a number indicating rank order of presumed shortening velocity.The largest, fastest fibres-F1-have low oxidative and, at best, moderate glycolytic capacities. Commonly adjacent to them are smaller, F2 fibres with variable but at least moderate metabolic capacities. F3 fibres are rarer and have on average the highest oxidative capacity, and at least moderate glycolytic capacity. They usually occur in the reddest parts of the muscle and, inRana, only in the vicinity of tonic fibres.Metabolically weak, classical amphibian tonic fibres (T5) occur in bothXenopus andRana, but onlyXenopus also has an S4 fibre type. This has moderate metabolic capacity and myosin properties suggesting it is probably capable of slow shortening as well as tonic hold. Immunohistochemically, S4 fibres are most similar to avian slow-twitch fibres.     

Histochemical and immunohistochemical investigation of muscle fibres in the sturgeon (Chondrostei; Acipenser)

The arrangement and innervation of lateral muscle and adductor mandibulae (AM) complex were examined histochemically and immunohistochemically in the sturgeon Acipenser transmontanus. Lateral muscle was arranged in myotomes in which the superficial slow-red muscle layer and the deep fast-white muscle layer were separated by an intermediate layer of pink muscle. The AM complex was composed of a small slow-red muscle layer, but the bulk of the muscle was composed of fast-white fibres. Pink fibres appeared both in an intermediate layer and scattered throughout the fast-white muscle. The innervation appeared to resemble that of elasmobranchs and some teleosts. Slow-red fibres of lateral muscle were multiply innervated, whereas fast-white muscle fibres were focally innervated at the myoseptal end. Pink fibres of lateral muscle and fast-white fibres of AM were focally innervated in the mid-region of the fibres. There were no significant differences between 5 month old and adult sturgeons except for a much better developed intermediate (pink) layer surrounding the lateral line in the adult.     

The fine structure of striated muscle fibres of tunica muscularis of the intestine in some teleosts

Summary The muscular layer of the fish oesophagus is made up exclusively of striated muscles, which form a circular and a longitudinal layer. The intestinal muscular layer of the tench, which is an exception among the vertebrates in this respect, consists of two layers of striated muscles and a layer of smooth ones. The organization of striated muscle fibres is described from the muscular layer of the alimentary canal in four species: the tench, crucian carp, gudgeon and stone-loach. The fibres of the oesophagus differ from each other in diameter, length of sarcomeres, glycogen content and, in the case of one species, organization of SR. On the basis of the organization of sarcomeres all the fibres examined must be counted among the slow-contracting ones (broad Z line). The sarcoplasmic reticulum is organized according to the Z type except for the fibres of the oesophageal muscles in which the SR represents the A-I type. Two types, en grappe and en plaque, of nerve endings have been observed. The presence of relatively large dense core vesicles seems to indicate their adrenergic origin.This work has been supported by the Polish Academy Sciences.     

Histochemical and immunochemical studies on mammalian striated muscle fibres

Summary In 15 rabbit and 2 human distinct types of striated muscle, it was shown that all fibres classified as type I (red) by NADH-diaphorase and myofibrillar ATPase reaction exhibit intense fluorescence when treated with a FITC-labelled antibody against human pectoral actomyosin. Type II (white) fibres showing minimal fluorescence, an intermediate fibre type can be differentiated by all three methods. In the rabbit, all three fibre types are found, whereas, in the human muscles studied, only type I and intermediate type fibres were found.Abbreviations ATPase adenosintriphosphatase (EC 3.6.1.3) - anti-PAM anti-human-pectoralis actomyosin - FITC fluoresceine-isothiocyanate     

Histochemical profile of articularis humeri muscle in the horse

In this study the histochemical fiber type analysis of the articularis humeri muscle of the horse was performed. This muscle is composed of type I and type IIA fibers. A large number of spindles has been observed and the presence of these receptors could help to understand the role played by this muscle.     

Histochemical heterogeneity of intrafusal muscle fibres in slow and fast skeletal muscles of the rat

Summary Intrafusal muscle fibres of the slow soleus (Sol) and fast vastus lateralis (VL) muscles of the rat were studied histochemically. Serial transverse sections were incubated for the localization of succinate dehydrogenase (SDH), alpha glycerophosphate dehydrogenase (GPD) and adenosine triphosphatase (ATPase). The latter was examined further after preincubation in acidic solution held at either low or room temperature (R_T). The bag₂ intrafusal fibres in both muscles displayed high regular and acid stable ATPase, but low SDH and GPD activities. Bag₁ intrafusal fibres showed low to moderate regular ATPase, a regional heterogeneity after R_T acid preincubation (low activity in juxtaequatorial and high in polar zones), moderate SDH, but low GPD reactions. In both muscles the chain fibres usually exhibited high ATPase for both regular and cold acid preincubated reactions, but usually low activity after R_T acid preincubation; they had high SDH but variable GPD activities. In Sol muscle, however, approximately 25% of spindles contained chain fibres that showed high acid-stable ATPase reaction after both cold and R_T acid preincubation. In contrast, chain fibres in some VL spindles had a characteristically low ATPase reaction even after cold acid preincubation. This study, therefore, has delineated the existence of an inherent heterogeneity among chain fibres (with respect to their histochemical reactions) in muscle spindles located within slow and fast muscles and also between those found within populations of either Sol or VL muscle spindles.     

Development of immunohistochemical characteristics of intrafusal fibres in normal and de-efferented rat muscle spindles

Intrafusal muscle fibres in adult muscle spindles differ in their myosin composition. After selective motor denervation intrafusal muscle fibres develop mature ultrastructural characteristics. In order to evaluate the role of fusimotor innervation on the maturation of the myosin composition of intrafusal muscle fibres we have examined with immunohistochemical techniques i) the postnatal development of muscle spindles in new-born rats and in 7-21 day old rats; ii) muscle spindles in the EDL of 21-day-old rats de-efferented at birth. For the characterization of myosins in intrafusal fibres we used three myosin antisera: antipectoral myosin, antiheart myosin and antiheart myosin adsorbed with muscle powder from the soleus muscle of guinea pig. We show in this study that during development intrafusal fibres change immunoreactivity and that in the absence of motor innervation bag fibres do not fully develop the myosin characteristics of control spindles. We conclude that the maturation of bag1 and bag2 fibres apparently requires next to the inductive influence of sensory axon terminals the presence and activity of fusimotor axons.     

Development of immunohistochemical characteristics of intrafusal fibres in normal and de-efferented rat muscle spindles

Summary Intrafusal muscle fibres in adult muscle spindles differ in their myosin composition. After selective motor denervation intrafusal muscle fibres develop mature ultrastructural characteristics. In order to evaluate the role of fusimotor innervation on the maturation of the myosin composition of intrafusal muscle fibres we have examined with immunohistochemical techniques i) the postnatal development of muscle spindles in new-born rats and in 7–21 day old rats; ii) muscle spindles in the EDL of 21-day-old rats de-efferented at birth. For the characterization of myosins in intrafusal fibres we used three myosin antisera: antipectoral myosin, antiheart myosin and antiheart myosin adsorbed with muscle powder from the soleus muscle of guinea pig. We show in this study that during development intrafusal fibres change immunoreactivity and that in the absence of motor innervation bag fibres do not fully develop the myosin characteristics of control spindles. We conclude that the maturation of bag₁ and bag₂ fibres apparently requires next to the inductive influence of sensory axon terminals the presence and activity of fusimotor axons.     

Histochemical differentiation of extrafusal muscle fibres of the anterior latissimus dorsi in the chick

Histochemical differentiation of the chick anterior latissimus dorsi (ALD) muscle was studied during embryonic development and after hatching. The two types of adult ALD tonic fibres (alpha' and beta') differentiate from a pool of acid and alkali-stable myofibrillar ATPase fibres. Intermediate stages of the transformation from beta' to alpha' were observed. At all developmental stages studied, a low percentage of formalin-resistant, alkali-stable and acid-labile ATPase fibres were observed. Such fibres have the histochemical properties of the alpha R or fast oxidative-glycolytic fibres and are assumed to be focally innervated.     

Recruitment and maximal diameter of axial muscle fibres in teleosts and their relationship to somatic growth and ultimate size

Growth of white axial muscle fibres of ten species of freshwater teleosts from five families (Cyprinidae, Centrarchidae, Percidae, Salmonidae, Esocidae) possessing widely different growth rates and ultimate sizes have been studied. The dynamics of muscle increase (i.e. increase in fibre numbers and/or diameter) appears to determine the ability for rapid somatic growth and large ultimate size in teleosts. Thus, the largest and fastest growing species (smallmouth bass, lake whitefish, rainbow trout, muskellunge) show evidence of sustained recruitment of muscle fibres to a large size, in contrast to the smaller and slower growing species (bluntnose minnow, longnose dace). Pumpkinseed, bluegill and yellow perch are all intermediate in fibre growth dynamics, growth and ultimate size between the smaller and larger species. Moreover, the ability of teleosts to grow rapidly and attain a large ultimate size is dependent on the body length at which recruitment of new muscle fibres into the growing axial muscle ceases. The regression equation, y =– 0.29 + 2.26 ( x ), showing the relationship (r = 0.95) between ultimate body length, x , and fork length at cessation of recruitment, y , indicated that for these teleosts, recruitment tends to cease when the fork length reaches about 44% of the ultimate body length. Possible mechanisms to account for this relationship are proposed, and the role of the ultimate fibre diameter in posing limits to the ultimate size of the species is discussed.     

Histochemical evidence of changes in fuel metabolism induced in red, white and intermediate muscle fibres of streptozotocin-treated rats

Summary The present study provides histochemical evidence supporting the operation of the glucose—fatty acid cycle in skeletal muscles taken 5 days after the administration of a single injection of streptozotocin. It also indicates that the cycle is more important in fast-oxidative-glycolytic (FOG) and slow-oxidative (SO) fibres than in fast-glycolytic (FG) fibres. Data from muscles taken 14 and 28 days after treatment suggest that lipid catabolism becomes progressively less important with time, and that muscles from longer-term diabetic rats rely on the aerobic and anaerobic breakdown of glucose by FOG and FG fibres to meet their cellular energy requirements. Although SO fibres appeared initially to be the least affected by steptozotocin-induced diabetes, the decline in their metabolic capabilities ultimately seemed to be greater than that in FOG fibres. Transformations in the biochemical characteristics of FOG and SO fibres occurred 14–28 days after streptozotocin treatment, in the absence of changes in actomyosin-ATPase activity. This supports the view that the division of skeletal muscle fibres into three or four distinct types on the basis of myosin- or actomyosin-ATPase activity is an oversimplification of the true situation.     

Correlation between biochemical properties and adaptive diversity of skeletal muscle myofibrils and myosin of some air-breathing teleosts

Functional properties of myofibrils and relative stability of myosin of five teleosts Channa punctata, Clarias batrachus, M astacembalus armatus, Labeo rohita and Catla catla adapted to different breathing modes were compared. Myofibrillar contractility and m-ATPase of air-breathing organ (ABO) possessing C.punctata and C. batrachus were low and least affected by pH in the range of 7.1-8.5. However, their myosin isoforms were relatively thermostable, more soluble at sub-neutral pH values, between 0.1 to 0.15 M KCl concentrations and less susceptible to a-chymotryptic digestion. In contrast, myofibrils and myosin of water-breather major carps L. rohita and C. catla were more contractile and susceptible to pH and salt concentrations. Thus, correlation between catalytic efficiency and relative stability of myofibrils and myosin of ABO-possessing teleosts was of reverse order and magnitude, as compared to water-breathers. Interestingly, myofibrils and myosin of the behavioral air-breather M. armnatus showed intermediate properties. The specific levels of m-ATPase of all the five teleosts were in conformity with the levels of metabolic marker, the lactate dehydrogenase. The effect of chymotryptic cleavage of 94 and 173 kDa domains on ATPase, individuality of peptide maps of MyHC isomers and perturbation of phenylalanine residues by urea implicated hydrophobic residues in stabilizing myosin structure in these fish. The present study suggests two apparent evolutionary modifications of myofibrils and myosin in ABO-possessing teleosts: (i), 'down-regulation' of ATPase that explains sluggishness of such species and, (ii), more stable molecular structure to support stress of air-breathing modes of life.     

Quantitative analysis of histochemical and immunohistochemical reactions in skeletal muscle fibres ofRana andXenopus

Summary Intensities of histochemical and immunohistochemical reactions in muscle fibres ofRana andXenopus have been estimated microphotometrically, and the data from serial sections statistically analysed. Quantitative validities of reactions and measurements have also been assessed against independent published evidence. It is concluded that NADH—tetrazolium reductase overestimates tonic-fibre aerobic capacities and the actomyosin ATPase reaction overestimates their contraction speeds. However, it appears that succinate dehydrogenase, despite being a near-equilibrium enzyme of particulate distribution, indicates the relative aerobic capacities of fibres with acceptable accuracy when lightly reacted. Capacities for aerobic and anaerobic metabolism are positively correlated over all types of fibre (r typically 0.6 for 200 fibres), perhaps as an adaptation to environmental hypoxia.Multivariate clusters (indicating fibre types) have been sought, using Ward's method with optimizing procedures (iterative relocation and multivariate-normal modelling). Cluster analysis confirms the subjective identifications of two slow/tonic types inXenopus (labelled T5 and S4) but of only one (T5) inRana. Division of the fast family twitch fibres into three types (F1–F3) in both genera, with metabolic capacity related inversely to apparent shortening velocity, is highly supportable by objective criteria. However, statistically significant subdivisions also present themselves.Rana F2 andXenopus F1 clusters can be bisected according to metabolic capacity; andXenopus F2 fibres fall into three subtypes reflecting different isomyosin contents. In the different types of twitch fibre, ratios of myofibrillar ATP consumption rate to aerobic capacity increase up to 30-fold with contraction speed, but anaerobic/aerobic ratios do so only 5-fold.