scholarly journals Expression of muscle-gene-specific isozymes of phosphorylase and creatine kinase in innervated cultured human muscle.

1986 ◽  
Vol 103 (4) ◽  
pp. 1423-1429 ◽  
Author(s):  
A Martinuzzi ◽  
V Askanas ◽  
T Kobayashi ◽  
W K Engel ◽  
S Di Mauro
Keyword(s):  
Spinal Cord ◽  
Creatine Kinase ◽  
Glycogen Phosphorylase ◽  
De Novo ◽  
Muscle Fibers ◽  
Total Activity ◽  
Human Muscle ◽  
Rat Embryo ◽  
Muscle Gene ◽  
Large Groups

Isozymes of creatine kinase and glycogen phosphorylase are excellent markers of skeletal muscle maturation. In adult innervated muscle only the muscle-gene-specific isozymes are present, whereas aneurally cultured human muscle has predominantly the fetal pattern of isozymes. We have studied the isozyme pattern of human muscle cultured in monolayer and innervated by rat embryo spinal cord explants for 20-42 d. In this culture system, large groups of innervated muscle fibers close to the ventral part of the spinal cord explant continuously contracted. The contractions were reversibly blocked by 1 mM d-tubocurarine. In those innervated fibers, the total activity and the muscle-gene-specific isozymes of both enzymes increased significantly. The amount of muscle-gene-specific isozymes directly correlated with the duration of innervation. Control noninnervated muscle fibers from the same dishes as the innervated fibers remained biochemically immature. This study demonstrated that de novo innervation of human muscle cultured in monolayer exerts a time-related maturational influence that is not mediated by a diffusable neural factor.

Regulation of glycogenolysis in human muscle at rest and during exercise

1982 ◽  
Vol 53 (3) ◽  
pp. 708-715 ◽  
Author(s):  
D. Chasiotis ◽  
K. Sahlin ◽  
E. Hultman
Keyword(s):  
Glycogen Phosphorylase ◽  
Total Activity ◽  
Human Muscle ◽  
Phosphorylase Activity ◽  
Michaelis Constant ◽  
Bicycle Exercise ◽  
Muscle Phosphorylase ◽  
Glycogen Utilization ◽  
Main Factors

The regulation of glycogenolysis in human muscle during isometric and dynamic exercise has been investigated. Total glycogen phosphorylase and synthase activities were unchanged during exercise. The fraction of phosphorylase in the alpha form at rest was estimated to be 20%, but the data indicate that the in vivo activity was low and critically dependent on the concentration of inorganic phosphate (Pi) in the muscle. Phosphorylase alpha increased initially 2.4-fold during isometric contraction and 1.6-fold during maximal bicycle exercise but reverted to or below the resting value at fatigue/exhaustion. At rest synthase I was 1713;48% of the total activity but decreased during exercise to about half of this value. The reciprocal changes in phosphorylase and synthase correlate with the enhanced rate of glycogenolysis during exercise. Michaelis constant (Km) for Pi was 27 mmol . l-1 for phosphorylase alpha and 7 mmol . l-1 for alpha + b. From consideration of the changes in Pi during exercise (to 20–30 mmol . l–1) it was concluded that Pi is one of the main factors determining phosphorylase activity and provides a link between phosphocreatine breakdown and glycogen utilization in muscle.

Histoenzymatic profile of human muscle cultured in monolayer and innervated de novo by fetal rat spinal cord

1988 ◽  
Vol 11 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Giuseppe Vita ◽  
Valerie Askanas ◽  
Andrea Martinuzzi ◽  
W. King Engel
Keyword(s):  
Spinal Cord ◽  
De Novo ◽  
Human Muscle ◽  
Rat Spinal Cord ◽  
Fetal Rat

Neurotrophins increase motoneurons' ability to innervate skeletal muscle fibers in rat spinal cord-human muscle cocultures

1996 ◽  
Vol 136 (1-2) ◽  
pp. 17-23 ◽  
Author(s):  
Serge Braun ◽  
Bernard Croizat ◽  
Marie-Claude Lagrange ◽  
Jean-Marie Warter ◽  
Philippe Poindron
Keyword(s):  
Skeletal Muscle ◽  
Spinal Cord ◽  
Muscle Fibers ◽  
Human Muscle ◽  
Rat Spinal Cord ◽  
Skeletal Muscle Fibers

Heterogeneity in regard to enzymes and metabolites within individual muscle fibers

1984 ◽  
Vol 246 (3) ◽  
pp. C288-C292 ◽  
Author(s):  
C. S. Hintz ◽  
M. M. Chi ◽  
O. H. Lowry
Keyword(s):  
Lactate Dehydrogenase ◽  
Coefficient Of Variation ◽  
Glycogen Phosphorylase ◽  
Muscle Fibers ◽  
Human Muscle ◽  
The Other ◽  
Mitochondrial Enzyme ◽  
Average Coefficient ◽  
Fiber Segment ◽  
Glycogen Particles

The possibility of variability along individual rat and human muscle fibers was assessed for four enzymes and four substances responsive to stimulation. Heterogeneity was determined by the differences between ends of fiber segments several millimeters long and by fluctuations in successive samples along the entire length of such segments. Among the enzymes, a cytosolic enzyme, lactate dehydrogenase, varied the least: average coefficient of variation (CV) of 5%. This is only a little greater than the analytic error. On the other hand, the CV for a mitochondrial enzyme, fumarase, was 13%. A mixed cytosolic-mitochondrial enzyme, malate dehydrogenase, was intermediate (CV of 9%). The CV for glycogen phosphorylase, which is normally bound to glycogen particles, was 34% along one fiber segment. Among the nonenzyme components, average CVs in stimulated fibers were 34, 20, 7, and 7%, respectively, for glucose 6-phosphate, phosphocreatine, ATP, and malate. Major differences were not random but developed gradually over distances of 0.5-2 mm along the fibers, and in some cases significant correlations between enzyme and metabolite levels were demonstrable.

scholarly journals Enzyme patterns in single human muscle fibers.

1978 ◽  
Vol 253 (22) ◽  
pp. 8269-8277
Author(s):  
C.V. Lowry ◽  
J.S. Kimmey ◽  
S. Felder ◽  
M.M. Chi ◽  
K.K. Kaiser ◽  
...  
Keyword(s):  
Muscle Fibers ◽  
Human Muscle ◽  
Enzyme Patterns
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