Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.3.5.1 (succinate dehydrogenase)
8,177 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The superior rectus muscle fibers of marlins, swordfish, sailfish and spearfish are modified for heat production at the expense of contractile ability. Although 'heater cells' are a muscle derivative (Block, 1986, 1991), the myoblast origin and developmental pathway of these thermogenic cells is unknown. To gain insight into heater cell origins, we characterized blue marlin superior rectus muscle and its heater tissue derivative with histochemical and immunological techniques. We specifically employed myosin ATPase and succinate dehydrogenase histochemical assays, and myosin heavy chain immunohistochemistry. Results revealed that marlin superior rectus muscles contain at least six distinct fiber types, and suggested the presence of both twitch and tonic fibers. Immunological results indicate that myosin is present within the thermogenic cells but not in myofibrillar lattices. The antibodies that recognized myosin in heater cells also labeled myosin in the twitch fibers of swimming muscle. In contrast, antibodies that labeled histologically defined tonic fibers did not label heater cells. These results suggest that heater cells and twitch fibers express the same myosin isoform, and establish a phenotypic connection between heater cells and twitch fibers. This conclusion is discussed in the context of the muscle-to-heater trajectory and the muscle fiber-type origin of heater cells.
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PMID:Histochemical and immunohistochemical studies on the origin of the blue marlin heater cell phenotype. 946 27

In young (15 weeks) and senescent (2 years) rats, the metabolic enzyme activities and the composition of myosin heavy chain (MHC) isoforms of the superficial masseter muscle were assessed by biochemical analysis. The succinate dehydrogenase activity and phosphofructokinase activity of the masseter muscle were significantly lower in senescent rats than in young rats. A large portion of the masseter muscle was composed of MHC IIb and IId isoforms in both young and senescent rats. As compared with young rats, no significant change in the composition of MHC isoforms was found in the masseter muscle of the senescent rats. These findings indicate that aging has a significant effect on the energy supply of the superficial masseter muscle.
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PMID:Biochemical properties of the superficial masseter muscle in the aging rat. 949 46

Cross-sectional areas and succinate dehydrogenase (SDH) activities of muscle fibers in the rat levator ani (LA) and bulbocavernosus (BC) were determined and compared with those of the soleus (SOL) and superficial (TAs) and deep (TAd) portions of the tibialis anterior (TA). In addition, cell body sizes and SDH activities of spinal motoneurons innervating the LA and BC were examined. Histochemical myofibrillar adenosine triphosphatase (mATPase) staining reactions following alkaline and acid preincubations revealed that all the muscle fibers in the LA and BC were type IIB. Gel electrophoresis, however, showed that the LA and BC contained 2.9 and 2.4% type IIx myosin heavy chain (MHC) isoform, respectively. Immunohistochemical analyses using MHC antibodies showed that the muscle fibers in the LA and BC had types IIx / IIa (approximately 3%) or type IIb MHC isoforms. The mean fiber cross-sectional areas in the LA and BC were significantly smaller than those in the SOL, TAs, or TAd. The mean fiber SDH activities in the LA and BC were significantly lower than those in the SOL or TAd, and similar to TAs. The population of alpha motoneurons innervating the LA and BC had similar SDH activities, irrespective of their cell body sizes. These data indicate that the LA and BC are comprised of a relatively homogeneous population of small, fast and low oxidative fibers innervated by a relatively homogeneous population of spinal motoneurons. These characteristics of the muscle fibers and motoneurons are consistent with their function in short, high-intensity activities.
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PMID:Perineal muscles and their innervation: metabolic and functional significance of the motor unit. 957 66

The aim of this study was to evaluate the cellular response of the diaphragm, extensor digitorum longus (EDL), and soleus (Sol) muscles to clinically relevant doses of cyclosporine administered to male rats over 4 wk. Control rats were provided with vehicle only. Muscle fiber types, cross-sectional areas, indexes of capillarity, and succinate dehydrogenase (SDH) activity were determined by quantitative histochemistry. Myosin heavy chain isoforms were identified by SDS-PAGE, and their proportions were measured by scanning densitometry. Serum cyclosporine level, 20-24 h after the last dose of cyclosporine, was 145 +/- 81 ng/ml. Final body weight and muscle mass were similar between the cyclosporine and control groups. In the diaphragm, EDL, and Sol, no differences were observed between the groups with regard to fiber type proportions, fiber cross-sectional areas, and proportions of myosin heavy chain isoforms. In the EDL, reductions, both in SDH activity in type I, IIx, and IIb fibers (-26 to -37%) and in indexes of capillarity (-18 to -37%), were noted. In the Sol, SDH activity and capillarity were similar between the groups. In the diaphragm of cyclosporine-treated rats, there was significant reduction in the number of capillaries around individual fibers (-5%), whereas levels of SDH activity tended to be lower. This suggests that activation history may in part determine muscle-specific responses to cyclosporine. We speculate that reduced oxidative activity and capillarity of some limb muscles contribute to reduced exercise capacity and the "deconditioned state" observed in patients receiving cyclosporine after successful solid-organ transplantation.
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PMID:Cellular adaptations of skeletal muscles to cyclosporine. 960 91

Cross-sectional area (CSA), succinate dehydrogenase (SDH), and alpha-glycerophosphate dehydrogenase (GPD) activities were measured in single fibres of adult rat medial gastrocneminus muscle (deep region) using quantitative histochemical procedures. The same fibres were identified in serial sections stained by immunohistochemistry with monoclonal antibodies specific for selected myosin heavy chain (MyHC) isoforms. The values of CSA, SDH and GPD activities formed a continuum, but significant differences in mean values were observed among fibre types of presumed homogeneous MyHC content. Type IIA fibres were the smallest, type IIB fibres were the largest, and type I and IIX fibres were intermediate. Type IIA fibres had the highest SDH activity, followed in rank order by type IIX, type I and type IIB. The average GPD activity was ranked according to fibre type such that IIB > IIX > IIA > I. Hybrid fibres co-expressing two MyHC isoforms generally showed intermediate mean CSA, SDH and GPD values lying between their respective pure MyHC fibre types. Across all fibres, there was an inverse relationship between SDH activity and CSA and between GPD and SDH activities, and a positive correlation between GPD and CSA. Moreover, a significant interdependence between CSA, SDH activity, GPD activity and MyHC content existed on a fibre-to-fibre basis, suggesting that the MyHC isoform expressed in a fibre is associated with differences in size, oxidative and glycolytic capabilities of muscle fibres. In fact, most of the fibres could be discriminated into discrete groups with the same MyHC content when their CSA, SDH and GPD values were considered together.
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PMID:Fibre size and metabolic properties of myosin heavy chain-based fibre types in rat skeletal muscle. 983 44

This study examined the influence of spinal cord injury (SCI) on affected skeletal muscle. The right vastus lateralis muscle was biopsied in 12 patients as soon as they were clinically stable (average 6 wk after SCI), and 11 and 24 wk after injury. Samples were also taken from nine able-bodied controls at two time points 18 wk apart. Surface electrical stimulation (ES) was applied to the left quadriceps femoris muscle to assess fatigue at these same time intervals. Biopsies were analyzed for fiber type percent and cross-sectional area (CSA), fiber type-specific succinic dehydrogenase (SDH) and alpha-glycerophosphate dehydrogenase (GPDH) activities, and myosin heavy chain percent. Controls showed no change in any variable over time. Patients showed 27-56% atrophy (P = 0.000) of type I, IIa, and IIax+IIx fibers from 6 to 24 wk after injury, resulting in fiber CSA approximately one-third that of controls. Their fiber type specific SDH and GPDH activities increased (P </= 0.001) from 32 to 90% over the 18 wk, thereby approaching or surpassing control values. The relative CSA of type I fibers and percentage of myosin heavy chain type I did not change. There was apparent conversion among type II fiber subtypes; type IIa decreased and type IIax+IIx increased (P </= 0.012). Force loss during ES did not change over time for either group but was greater (P = 0.000) for SCI patients than for controls overall (27 vs. 9%). The results indicate that vastus lateralis muscle shows marked fiber atrophy, no change in the proportion of type I fibers, and a relative independence of metabolic enzyme levels from activation during the first 24 wk after clinically complete SCI. Over this time, quadriceps femoris muscle showed moderately greater force loss during ES in patients than in controls. It is suggested that the predominant response of mixed human skeletal muscle within 6 mo of SCI is loss of contractile protein. Therapeutic interventions could take advantage of this to increase muscle mass.
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PMID:Influence of complete spinal cord injury on skeletal muscle within 6 mo of injury. 988 50

Myofibrillar ATPase (mATPase), succinate dehydrogenase (SDH) and alpha-glycerophosphate dehydrogenase (GPD) activities and cross-sectional area (CSA) were measured in fibres of rat medial gastrocnemius muscle using quantitative histochemistry. The same fibres were typed immunohistochemically using monoclonal antibodies specific to selected myosin heavy chain (MHC) isoforms. The values of mATPase, SDH, GPD and CSA formed a continuum, but significant differences in mean values were observed among fibre types of presumed homogeneous MHC content. Type I fibres had the lowest mATPase activity, followed in rank order by type IIA < type IID/X < type IIB. Type IIA fibres had the highest SDH activity, followed in rank order by type IID/X > type I > type IIB. The mean GPD activity was consistently ranked according to fibre type such that type IIB > type IID/X > type IIA > type I. Type IIA fibres were the smallest, type IIB fibres were the largest and types I and IID/X were of intermediate size. Significant interrelationships between mATPase, SDH, GPD and CSA values were found on a fibre-to-fibre basis. Consequently, discrimination of fibres according to their MHC content was possible on the basis of their mATPase, SDH, GPD and CSA profiles. These intrafibre interrelationships suggest that the MHC isoform is associated with phenotypic differences in contractile, metabolic and size properties of muscle fibre types.
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PMID:Interrelationships of myofibrillar ATPase activity and metabolic properties of myosin heavy chain-based fibre types in rat skeletal muscle. 1021 27

We studied the effects of four variables on the histological properties of three body wall muscles-rectus abdominis (RA), transversus abdominis (TA), and external oblique (EO)-from pregnant rats. The variables examined were (1) gestation period; (2) cage design; (3) the effect of a midline laparotomy, performed to determine fetus numbers; and (4) exposure to a nine-day spaceflight. We measured fiber cross-sectional area (CSA), metabolic enzyme levels (succinate dehydrogenase, glycerophosphate dehydrogenase), and myosin heavy chain (MHC) immunoreactivity in samples from each muscle. A major effect of spaceflight was an increase of 42-171% in fibers double-labeled for MHC in all three muscles. Based on fiber CSA, the TA and RA muscles showed signs of stretching with increased gestation; i.e., the CSA decreased 11-12% over a nine-day period. The EO, a torso rotator, hypertrophied by 9% in rats group-housed in cages with a complex 3-D structure, compared to controls housed singly in standard flat-bottom cages. The TA and EO, whose contractions would pull on the suture line, showed signs of atrophy in laparotomized animals, exhibiting a 12% decrease in muscle fiber CSA. Exposure to weightlessness is known to induce atrophy in most skeletal muscles. Surprisingly, the EO actually hypertrophied 11% in our flight animals; however, this can be explained by the fact that those rats actively rotated their torsos seven times more often than ground controls. The flight rats also had twice as many contractions as controls. However, they were still able to give birth on time postflight.
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PMID:Effects of laparotomy, cage type, gestation period and spaceflight on abdominal muscles of pregnant rodents. 1040 16

Samples of semitendinosus muscle from 28 male cattle (18 Salers and 10 Limousins) were taken at 10 months (biopsy) and at 16 months of age (at slaughter). The animals had received the same diet and were slaughtered after the same duration of fattening. The activities of isocitrate dehydrogenase and lactate dehydrogenase were measured in the muscle samples. The five lactate dehydrogenase isoenzymes were separated by electrophoresis under non-denaturing conditions and assayed by densitometry. Fibres were identified by histochemistry by myofibrillar ATPase and succinate dehydrogenase activities as SO (slow oxidative), FOG (fast oxidative glycolytic) or FG (fast glycolytic), and by immunohistochemistry by their reaction to monoclonal antibodies specific to slow and fast myosin heavy chain reactions in I, IIC, IIA, IIAB and IIB type fibres. The isocitrate dehydrogenase activity was not modified between 10 and 16 months of age; the lactate dehydrogenase activity decreased and was correlated with an increase in the proportion of the H isozyme to the detriment of the proportion of the M form. This period was characterized by an increase in fibre size, increased expression of MHC IIa, resulting in more IIA fibres, less IIB fibres, and an increase in the percentage of type IIAB fibres, however the proportions of SO, FOG and FG, when analysed statistically, were not modified between 10 and 16 months of age.
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PMID:Changes in the metabolic and contractile characteristics of muscle in male cattle between 10 and 16 months of age. 1041 83

Development of muscle is critically dependent on several hormones which in turn are regulated by nutritional status. We therefore determined the impact of mild postnatal undernutrition on key markers of myofibre function: type I slow myosin heavy chain (MyHC) isoform, myosin ATPase, succinate dehydrogenase and alpha-glycerophosphate dehydrogenase. In situ hybridization, immunocytochemistry and enzyme histochemistry were used to assess functionally distinct muscles from 6-week-old pigs which had been fed an optimal (6% (60 g food/kg body weight per d)) or low (2% (20 g food/kg per d)) intake for 3 weeks, and kept at 26 degrees C. Nutritional status had striking muscle-specific influences on contractile and metabolic properties of myofibres, and especially on myosin isoform expression. A low food intake upregulated slow MyHC mRNA and protein levels in rhomboideus by 53% (P < 0.01) and 18% (P < 0.05) respectively; effects in longissimus dorsi, soleus and diaphragm were not significant. The oxidative capacity of all muscles increased on the low intake, albeit to varying extents: longissimus dorsi (55%), rhomboideus (30%), soleus (21%), diaphragm (7%). Proportions of slow oxidative fibres increased at the expense of fast glycolytic fibres. These novel findings suggest a critical role for postnatal nutrition in regulating myosin gene expression and muscle phenotype. They have important implications for optimal development of human infants: on a low intake, energetic efficiency will increase and the integrated response to many metabolic and growth hormones will alter, since both are dependent on myofibre type. Mechanisms underlying these changes probably involve complex interactions between hormones acting as nutritional signals and differential effects on their cell membrane receptors or nuclear receptors.
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PMID:Postnatal regulation of myosin heavy chain isoform expression and metabolic enzyme activity by nutrition. 1102 69


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