Effects of trimetazidine and selenium on high-frequency fatigue in isolated rat diaphragm muscle

2003 ◽  
Vol 20 (5) ◽  
pp. 261-269 ◽  
Author(s):  
Mustafa Emre ◽  
Ibrahim Karayaylali ◽  
Mustafa San
Keyword(s):  
High Frequency ◽  
Diaphragm Muscle ◽  
Rat Diaphragm ◽  
Isolated Rat

The acute effect of trimetazidine on the high frequency fatigue in the isolated Rat diaphragm muscle

2004 ◽  
Vol 27 (6) ◽  
pp. 646-652 ◽  
Author(s):  
Mustafa Emre ◽  
Ibrahim Karayaylali ◽  
Mustafa San ◽  
Ayşe Demirkazik ◽  
Servet Kavak
Keyword(s):  
High Frequency ◽  
Acute Effect ◽  
Diaphragm Muscle ◽  
Rat Diaphragm ◽  
Isolated Rat

Estimates of quantal-release and binomial statistical-release parameters at rat neuromuscular junction

1977 ◽  
Vol 233 (5) ◽  
pp. C157-C163 ◽  
Author(s):  
D. F. Wilson
Keyword(s):  
Intracellular Recording ◽  
High Frequency ◽  
Action Potentials ◽  
Indirect Method ◽  
Nerve Impulse ◽  
Muscle Action ◽  
Rat Diaphragm ◽  
Quantal Release ◽  
End Plate ◽  
Isolated Rat

Quantal-release and binomial statistical-release parameters were examined in the isolated rat diaphragm phrenic nerve preparation. The muscle resting potentials were reduced by cutting the muscle fibers to prevent muscle action potentials and contractions. The cutting technique was modified to allow persistent observation of miniature end-plate potentials (MEPPs) and end-plate potentials (EPPs) with intracellular recording techniques. Direct estimates of quantal release were examined and compared with predicted binomial and Poisson distributions. The results indicate that release is binomial when the nerve is stimulated with low- or high-frequency stimuli. The indirect method of estimating quantal release (variance method), which assumes release is described by a Poisson distribution, seriously overestimates quantal release. The binomial analysis indicates that the statistical store is small (less than 90 quanta) and that most of these quanta are released with each nerve impulse.

scholarly journals The influence of insulin on the metabolism of glucosamine in the isolated rat diaphragm muscle

1970 ◽  
Vol 119 (1) ◽  
pp. 27-30 ◽  
Author(s):  
Anne Beloff-Chain ◽  
E. B. Chain ◽  
K. A. Rookledge
Keyword(s):  
Phosphate Esters ◽  
Diaphragm Muscle ◽  
Rat Diaphragm ◽  
Normal Muscle ◽  
Isolated Rat

1. The influence of insulin on the metabolism of [1-14C]glucosamine by diaphragm muscle from normal rats and rats rendered diabetic with streptozotocin has been studied. 2. The glucosamine was converted into glucosamine 1-phosphate, glucosamine 6-phosphate, glycogen, lactate and small amounts of other unidentified intermediates. 3. Insulin increased the incorporation of 14C into glycogen in both the normal and diabetic muscle, but did not increase the formation of the glucosamine phosphate esters. 4. The 14C content in the glycogen was present partly as glucose and partly as glucosamine; there was significantly more [14C]glucose in the glycogen of the diabetic muscle than in that of the normal muscle.

Almitrine and doxapram decrease fatigue and increase subsequent recovery in isolated rat diaphragm

1997 ◽  
Vol 83 (1) ◽  
pp. 52-58 ◽  
Author(s):  
Michelle McGuire ◽  
Michael F. Carey ◽  
John J. O’Connor
Keyword(s):  
Muscle Activation ◽  
Isometric Force ◽  
Radical Scavenging ◽  
Diaphragm Muscle ◽  
Rat Diaphragm ◽  
Subsequent Recovery ◽  
Group 2 ◽  
Isolated Rat ◽  
Group 1

McGuire, Michelle, Michael F. Carey, and John J. O’Connor.Almitrine and doxapram decrease fatigue and increase subsequent recovery in isolated rat diaphragm. J. Appl. Physiol. 83(1): 52–58, 1997.—The effects of almitrine bimesylate and doxapram HCl on isometric force produced by in vitro rat diaphragm were studied during direct muscle activation at 37°C. Doxapram and almitrine ameliorate respiratory failure clinically by indirectly increasing phrenic nerve activity. This study was carried out to investigate possible direct actions of these agents on the diaphragm before and after fatigue of the fibers. Two age groups of animals were chosen [6–14 wk ( group 1) and 50–55 wk ( group 2)] because it is known that increasing age decreases a muscle fiber’s resistance to fatigue. Muscle strips were isolated from both group 1 and group 2 and directly stimulated (2-ms pulse duration, 5–15 V) to produce twitch tensions of 1.3 and 2.1 N/cm2, respectively. At low concentrations, doxapram (≤20 μg/ml) and almitrine (≤12 μg/ml) had no effect on twitch contraction or 100-Hz tetanic tension. However, 40 μg/ml doxapram and 30 μg/ml almitrine increased twitch tension by 9.0 ± 1.4 and 11.6 ± 1.9%, respectively, in animals of group 2( n = 5). A fatigue protocol consisting of low-frequency stimulation (30-Hz trains, 250-ms duration every 2 s for 5 min) caused a reduction of twitch tension in animals of group 1 (48 ± 4% of control) and group 2 (28 ± 4% of control). At 90 min postfatigue, the twitch tension recovered to 72 ± 3 and 42 ± 2% of control values in group 1 and group 2, respectively. In the presence of doxapram (20 μg/ml), there was a significant increase in the recovery of twitch tension at 90 min in group 1 and group 2 (84.5 ± 3.2 and 80.1 ± 2.8%, respectively) compared with controls at 90 min postfatigue. In the presence of almitrine (12 μg/ml), there was a full recovery from fatigue in group 1 animals (100% of control) and a recovery to 95.6 ± 2.1% of control in group 2 animals at 90 min. These results demonstrate a significant improvement in the rapidity and magnitude of recovery from fatigue in the rat diaphragm muscle in the presence of both doxapram and, especially, almitrine. These effects may be due to changes in intracellular calcium, ADP/ATP ratios, or oxygen free radical scavenging.

scholarly journals Influence of some mononucleotides and their corresponding nucleosides on the metabolism of carbohydrates in the isolated rat diaphragm muscle

1965 ◽  
Vol 97 (2) ◽  
pp. 565-568 ◽  
Author(s):  
A Beloff-Chain ◽  
P Betto ◽  
W Bleszynski ◽  
R Catanzaro ◽  
EB Chain ◽  
...  
Keyword(s):  
Glucose Metabolism ◽  
Incubation Period ◽  
Glycogen Synthesis ◽  
Diaphragm Muscle ◽  
Maximum Effect ◽  
Rat Diaphragm ◽  
Oxidation Of Glucose ◽  
Isolated Rat

1. The influence of ATP on glucose metabolism was studied in the isolated rat diaphragm; it was shown that ATP increases the oxidation of glucose and the aerobic conversion of glucose into lactate, whereas it decreases glycogen synthesis. There was no influence of ATP on the anaerobic formation of lactate from glucose. 2. A maximum effect of ATP on the oxidation of glucose (about 160% increase) was obtained in the presence of 10mm-ATP; in the presence of 2mm-ATP the effect was about 65%, and was approximately constant from 10 to 90min. incubation period. 3. In a phosphate-free tris-buffered medium the oxidation of glucose was considerably decreased, but the percentage stimulation by ATP was about the same as in a phosphate-buffered medium. 4. ATP was shown to increase the oxidation of fructose, glucose 6-phosphate, glucose 1-phosphate, fructose 1,6-diphosphate and, to a much smaller extent, pyruvate. 5. ADP stimulated the oxidation of glucose to the same extent as ATP at a concentration of 2mm and the effect with AMP was only slightly less; IMP and adenosine had only a small stimulatory effect at this concentration, whereas inosine had no effect.

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