scholarly journals Maintenance of structural and functional characteristics of skeletal-muscle mitochondria and sarcoplasmic-reticular membranes after chronic ethanol treatment

1991 ◽  
Vol 274 (2) ◽  
pp. 565-573 ◽  
Author(s):  
F Cardellach ◽  
T F Taraschi ◽  
J S Ellingson ◽  
C D Stubbs ◽  
E Rubin ◽  
...  

The effect of long-term ethanol intake on the structural and functional characteristics of rat skeletal-muscle mitochondria and sarcoplasmic reticulum was investigated. Functionally, skeletal-muscle mitochondria were characterized by a high respiratory control index and ADP/O ratio and a high State-3 respiration rate with different substrates. These parameters were not significantly different in preparations from control and ethanol-fed rats, except for a small increase in the rate of oxidation of alpha-oxoglutarate/malate in the latter. In submitochondrial particles from the two groups of animals there was no significant difference in cytochrome content, ATPase activity or the activity of respiratory-chain complexes. Mitochondrial membranes from untreated and ethanol-fed rats showed no difference in the baseline e.s.r. order parameter, and both preparations were equally sensitive to disordering by ethanol in vitro. Similarly, sarcoplasmic-reticulum preparations were not significantly affected by long-term ethanol feeding with respect to Ca2(+)-ATPase activity or in baseline order parameter and susceptibility to membrane disordering by ethanol in vitro. These membranes were also equally sensitive to degradation by exogenous phospholipase A2. Ethanol feeding did not alter the class composition of mitochondrial or sarcoplasmic-reticulum membrane phospholipids, nor the acyl composition of individual phospholipid classes. Specifically, the changes in acyl composition that characteristically occur in liver microsomal phosphatidylinositol and liver mitochondrial cardiolipin were not observed in the corresponding phospholipids from skeletal-muscle membranes. In experiments where membrane preparations from liver and skeletal muscle from the same ethanol-fed animals were compared, the liver membranes developed membrane tolerance, with the muscle membranes retaining normal sensitivity to disordering effects by ethanol. It is concluded that: (a) different tissues from the same animals differ in their susceptibility to ethanol; (b) the tissue-specific lack of development of membrane tolerance correlates with a lack of chemical changes in the phospholipids and with a retention of normal function of mitochondria and sarcoplasmic reticulum; (c) effects of chronic ethanol intake on muscle function are not due to a defect in the mitochondrial energy supply.

2006 ◽  
Vol 38 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Rachel Navet ◽  
Ange Mouithys-Mickalad ◽  
Pierre Douette ◽  
Claudine M. Sluse-Goffart ◽  
Wieslawa Jarmuszkiewicz ◽  
...  

1995 ◽  
Vol 73 (8) ◽  
pp. 1154-1164 ◽  
Author(s):  
E. R. Chin ◽  
H. J Green ◽  
F. Grange ◽  
J. Dossett-Mercer ◽  
P. J. O'Brien

The role of prolonged electrical stimulation on sarcoplasmic reticulum (SR) Ca2+sequestration measured in vitro and muscle energy status in fast white and red skeletal muscle was investigated. Fatigue was induced by 90 min intermittent 10-Hz stimulation of rat gastrocnemius muscle, which led to reductions (p < 0.05) in ATP, creatine phosphate, and glycogen of 16, 55, and 49%, respectively, compared with non-stimulated muscle. Stimulation also resulted in increases (p < 0.05) in muscle lactate, creatine, Pi, total ADP, total AMP, IMP, and inosine. Calculated free ADP (ADPf) and free AMP (AMPf) were elevated 3- and 15-fold, respectively. No differences were found in the metabolic response between tissues obtained from the white (WG) and red (RG) regions of the gastrocnemius. No significant reductions in SR Ca2+ATPase activity were observed in homogenate (HOM) or a crude SR fraction (CM) from WG or RG muscle following exercise. Maximum Ca2+uptake in HOM and CM preparations was similar in control (C) and stimulated (St) muscles. However, Ca2+uptake at 400 nM free Ca2+was significantly reduced in CM from RG (0.108 ± 0.04 to 0.076 ± 0.02 μmol∙mg−1protein∙min−1in RG–C and RG–St, respectively). Collectively, these data suggest that reductions in muscle energy status are dissociated from changes in SR Ca2+ATPase activity in vitro but are related to Ca2+uptake at physiological free [Ca2+] in fractionated SR from highly oxidative muscle. Dissociation of SR Ca2+ATPase activity from Ca2+uptake may reflect differences in the mechanisms evaluated by these techniques.Key words: sarcoplasmic reticulum, contractile activity, Ca2+sequestration, energy status, red and white gastrocnemius.


Endocrinology ◽  
2008 ◽  
Vol 149 (12) ◽  
pp. 6262-6271 ◽  
Author(s):  
Ana Paula Arruda ◽  
Luisa A. Ketzer ◽  
Mariana Nigro ◽  
Antonio Galina ◽  
Denise P. Carvalho ◽  
...  

Brown adipose tissue (BAT) is involved in rat and mice thermoregulation, and heat produced by BAT depends on the concerted action of thyroid hormones and catecholamines. Little is known about cold-induced thermogenesis in mammals that have little or no BAT, such as rabbits. In these animals, thermogenesis primarily occurs in skeletal muscle. In this work, we have studied the effect of cold acclimation (4 C for 10 d) in normal and hypothyroid rabbits. It is known that hypothyroid rats die after a few hours of cold exposure. We now show that, different from rats, hypothyroid rabbits sustain their body temperature and survive after 10 d cold exposure. When compared with rabbits kept at room temperature, the muscles of cold-exposed rabbits showed a dark red color characteristic of oxidative muscle fibers. According to this pattern, we observed that in both normal and hypothyroid rabbits, cold exposure promotes an increase in oxygen consumption by skeletal muscle mitochondria. Moreover, in red muscle, cold acclimation induces an increase in the expression and activity of sarcoplasmic reticulum Ca2+ ATPase isoform 1 (SERCA1), one of the muscle enzymes involved in heat production. We conclude that rabbit cold tolerance is probably related to increased muscle oxidative metabolism and heat production by SERCA1 and that these changes are not completely dependent on normal thyroid function.


1975 ◽  
Vol 63 (1) ◽  
pp. 131-142
Author(s):  
H. Huddart ◽  
A. J. Syson

1. KCl-induced depolarization resulted in a large stimulation of the 45Ca efflux from both cockroach skeletal muscle and rat ileal smooth muscle. 2. Caffeine (10 mM) induced a large stimulation of 45Ca efflux from skeletal muscle, but a fall in the efflux from ileal muscle, especially if the efflux was previously stimulated by KCl depolarization. 3. Caffeine inhibited calcium uptake by skeletal muscle mitochondria and sarcoplasmic reticulum, was without effect on ileal muscle mitochondria, but significantly increased caclium binding by ileal muscle membrane vesicular preparations. 4. The induction of contractures and stimulation of 45Ca efflux in skeletal muscle by caffeine are clearly related to inhibition of intracellular calcium binding by the sarcoplasmic reticulum and mitochondria. 5. The relaxation of ileal muscle by caffeine and the inhibition of fibre calcium efflux correlate well with caffeine enhancement of intracellular calcium binding. These experiments suggest that the membrane vesicular compartment may be the main agency centrally involved in fibre calcium regulation in this muscle during the contraction-relaxation cycle.


2018 ◽  
Vol 1 (3) ◽  
Author(s):  
Tianhao Wen ◽  
Hao Su ◽  
Zhongye Jiang ◽  
Jia Shao

Objective To observe the temporal variation of Beclin1 and Bnip3 protein in skeletal muscle aging degeneration by constructing the aged rat model, and to observe the effect of HIIT intervention on the changes of Beclin1 and Bnip3 protein and the relationship between the two. It provides a theoretical basis for the effect of exercise on the aging degeneration of skeletal muscle by affecting the level of mitochondrial autophagy. Methods 40 male Wistar rats aged 8 months were randomly divided into quiet control group (C) and HIIT intervention group (H). After the rats entered the animal room for one week of adaptive feeding and exercise, the rats in the C group did not exercise, and the H group exercise alternately based on the maximum oxygen uptake test results of the rats with the 70%-90%-50%VO2max intensity. Once every two weeks, the maximal oxygen uptake of the rats in group H and group C was tested. Group H underwent 50min/ days, 5 days / weeks, and lasted for 16 weeks. The rats in the two groups were randomly selected after the first VO2 test and eighth and sixteenth weeks after intervention. After anesthesia, blood was collected from the abdominal aorta and soleus tissue was obtained. The ROS activity in soleus muscle was tested by fluorescence enzyme labeling method. Isolation of mitochondria from soleus muscle using tissue mitochondria Isolation Kit, and the expression of Beclin1 and Bnip3 in the mitochondria of the soleus muscle was tested by Western blot. The Image Lab 4 software was used to collect the data of the protein test strip, and the SPSS 17 software was used to analyze the data. The results of the data analysis were presented in the form of mean standard deviation. In the process of protein strip analysis, the relative value of the protein content of each sample was obtained by the gray scale analysis method. The results of the first sampling were taken as the baseline value, and the ratio of the H group in the C group of 8 weeks and 16 weeks was obtained with the baseline value, that is, the relative value of the protein content. Then, repeated measurement of variance analysis was used to analyze the differences of different indicators at baseline level, 8 weeks and 12 weeks between group C and group H. The independent sample T test was used without interaction effect, and multivariate analysis of variance was used. A significant level of alpha =0.05 is set. Results (1) the content of ROS in skeletal muscle of rats was related to the process of natural aging (F=119.314, P < 0.001), and the level of ROS would rise with the process of natural collars (F=28.884, P=0.001; F=127.607, P < 0.001) through the comparison of the time points in the group C and the H group. At the same time, the level of ROS in group H was lower than that in group C, but there was no significant difference (P=0.310). And the interaction effect of time and exercise mode (HIIT) will not affect the result (F=0.814, P=0.477). But the growth rate of ROS in group H was lower than that in C group. ⑵Exercise, time change and their interaction did not affect the content of Beclin1 in rat skeletal muscle mitochondria (P > 0.05). ⑶The mitochondrial Bnip3 content in H group and C group was significantly different at 8 weeks (F=14.500, P=0.001), H group was significantly higher than that in C group, but there was no significant difference in mitochondrial Bnip3 content at the 16 week (F=0.090, P=0.767), and the Bnip3 content of skeletal muscle mitochondria changed with age (F=20.852, 0.001). The trend of H increased, but then decreased. There was a linear trend (F=6.950, P=0.005) between the level of mitochondrial Bnip3 content and the intergroup factors (time point changes) and the interaction between time and HIIT movement in rats. Conclusions  With the process of aging, (1) The content of ROS in skeletal muscle of rats increased significantly, while long-term HIIT training could delay the increase, but the best exercise time was unknown. (2) There was no obvious change in Beclin1 content in skeletal muscle mitochondria of rats, and HIIT training had no obvious effect on it. However, the changes in mitochondrial Beclin1 content relative to the total Beclin1 content of skeletal muscle need to be further studied; (3) The content of Bnip3 in skeletal muscle mitochondria in rats is increased, and long-term HIIT training has a delayed effect.


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