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The purpose of this study was to examine effects of moderate-intensity endurance exercise on reactive oxygen species production and leukocyte activation markers in young and middle-aged persons. Blood samples were collected before and after the jogging of 10 km. Although cytokines recruiting and priming neutrophils and monocytes were released into the circulation and functional after the jogging of 10 km, reactive oxygen metabolites-derived compounds (d-ROMs) were not significantly increased. It was indicated that chemokines and leukocyte activation markers at rest were increased with aging, and that might be accompanied by the higher level of d-ROMs in the elderly.<br>
RESUMO
The effects of resistance training (RT) on serum adipocytokine levels were investigated in rats. Male rats were allocated either to a RT group or a control (C) group. The RT group performed RT by climbing 1-m high cages for access to water. The epididymal, retroperitoneal, and inguinal fat pad weights of the RT were significantly lesser than those of the C group. A significantly lower serum insulin concentration was observed in the RT group than in the C group ; no significant group difference was observed in the plasma glucose concentration. The serum leptin level was significantly lower in the RT group than in the C group. On the other hand, no significant difference existed in the TNF-α, adiponectin, and resistin levels between the two groups. The results indicate that the RT improved the whole-body insulin sensitivity and induced differential effects on the serum adipocytokine levels in rats.
RESUMO
In order to find the cause behind the difference in the pattern of oxygenation between thigh and calf muscles during an incremental cycling exercise, we investigated the relationship between oxygenation and surface myoelectric activity. Five healthy male subjects performed the five 6-min cycling exercises of 50, 100, 150, 200 and 250 watts. We measured oxygenated hemoglobin/myoglobin (oxy-Hb/Mb) on continuous wave near infrared spectroscopy (NIR) and myoelectric activity with surface electrodes (EMG) . The NIR probe and electrodes were positioned on the vastus lateralis muscle (VL) and lateral gastrocnemius muscle (LG) of the right leg. The relative change in oxy-Hb/Mb was estimated by regarding the oxy-Hb/Mb level in the resting condition as 100% and that obtained during thigh occlusion as 0 %. The mean values of oxy-Hb/Mb and integrated EMG (iEMG) determined ranged from 5'30'' to 6'00'' at each work rate. In the VL, the oxy-Hb/Mb level decreased slightly at 50 and 150 watts (99.2±6.8% and 84.6±12.9%), followed by a more prom-inent decrease at 200 and 250 watts (74.9±11.9 and 65.2±9.6%) . The iEMG increased slowly at 50 and 150 watts (24.9±8.8 and 38.0±8.8μV), and a rapid increment occurred at 200 and 250 watts (49.6±13.0 and 57.3±19.6μV) . In the LG, however, the oxy-Hb/Mb level was decreased slightly at 50 and 200 watts (97.3±11.1 and 87.4±6.4%) and a rapid decrement occurred at 250 watts (74.1±6.0%) . The iEMG increased slowly at 50 and 200 watts (18.3±9.4 and 30.5±8.8 μV), and a rapid increment occurred at 250 watts (38.5±8.9 μV) . There was a significant negative correlation between the oxy-Hb/Mb level and iEMG in the VL (r=-0.587, p<0.001) and in the LG (r=-0.599, p<0.001) . From these results, we speculated that the difference in the relative change of oxy-Hb/Mb between the vastus lateralis and the lateral gastrocnemius muscle was due to the difference of increase pattern of muscle activity accompanied by an increase in exercise intensity in these two muscles.
RESUMO
Myosin light chain patterns were examined in single fibers from the extensor digitorum longus (EDL) and soleus muscles of Wistar strain rats. The fiber type composition of both muscles was also determined to estimate the relationship between myosin light chain patterns and histochemical fiber types.<BR>The results were summarized as follows ;<BR>1. All of single fibers from the EDL muscle was typical fast type which contained fast light chains only (fLC 1·fLC 2·fLC 3), except that there was one mixed type fiber cotaining both fast and slow light chains (fLC 1·fLC 2·sLC 1·sLC 2) .<BR>2. There were two myosin light chain patterns in single fibers from the soleus muscle. One was typical slow type which contained slow light chains only (sLC1·sLC 2) and the other, mixed type in which fast and slow light chains coexisted. Mixed type fibers were divided into eight groups based on the light chain composition. The percentage occurence of typical slow type and mixed type fibers was 35.4% and 64.6%, respectively.<BR>3. The average percentage of type II fibers was 94.6% in the EDL muscle 5.4% in the soleus muscle.<BR>4. These results suggest that both fast and slow skeletal muscles contain mixed type fibers. The results further imply that in slow skeletal muscle, myosin light chain pattern of mixed type occurs not only in type II but also in type I fibers.
RESUMO
Postnatal changes of myosin light chain patterns and enzyme activities were examined in the fast extensor digitorum longus and slow soleus muscles of Wistar strain rats aged 5, 10 and 20 weeks. Sex differences in each parameter were also studied.<BR>The results were summarized as follows:<BR>1) The extensor digitorum longus muscle contained mostly the fast light chains (fLC 1, fLC 2, fLC 3) . However, small amounts of the slow light chains (sLC 1, sLC 2) were also found. There were no postnatal changes in myosin light chain patterns in the extensor digitorum longus muscle.<BR>2) The soleus muscle contained slow and fast light chains (sLC 1, sLC 2, fLC 1, fLC 2, fLC 3) in 5 weeks of age, slow light chains being more predominant than fast light chains. There were an increase in the percentage of slow light chains and a concomitant decrease in the percentage of fast light chains with age. FLC 3 which was found at 5 weeks of age did not be detected in the soleus muscle from the 20-week-old rat.<BR>3) PFK activity decreased significantly with age in the soleus muscle, whereas there was no postnatal changes in PFK activity in the extensor digitorum longus muscle.<BR>4) There was a significant increase in SDH activity during growth in both the extensor digitorum longus and soleus muscles with the exception of the extensor digitorum longus muscle from the male rat.<BR>5) The enzyme activity ratio (PFK/SDH) significantly decreased with age in all muscles with an exception of the extensor digitolum longus muscle from the male rat.<BR>6) In the soleus muscle an increase in the relative amount of slow type myosin light chains and a decrease in the enzyme activity ratio (PFK/SDH) occurred coincidentally during postnatal growth.<BR>7) In most cases no significant sex differences existed in myosin light chain pattern and enzyme activity examined.
RESUMO
Sex difference in enzyme activities of the skeletal muscle were examined in rats aged 10 and 35 weeks. At 10 and 35 weeks of age, animals were anesthetized with ether and weighed. M, gastrocnemius, m.extensor digitorum longus and m.soleus were removed from both legs under pentobarbital anethesia and weighed. These muscles were used for the determination of myosin ATPase activity, phosphofruktokinase (PFK) activity, succinate dehydrogenase (SDH) activity and non-collagenous protein (NCP) content.<BR>The results were summarized as follows:<BR>1) Thirty-five week-old rats had heavier body and muscle weights than 10-weekold rats in both sexes and males had significantly heavier body and muscle weights than females at both 10 and 35 weeks of age.<BR>2) Similar tendency was observed with regard to total NCP content. Furthermore, it was found that total NCP content was positively correrated to muscle weight (r=0.871, r=0.909 and r=0.871 in m. gastrocnemius, m.extensor digitorum longus and m.soleus, respectively) . However, no significant difference in NCP content per wet weight was found between both sexes and between different age groups.<BR>3) Myosin ATPase activity tended to be lower at 35 weeks of age than at 10 weeks of age, the tendency being the most prominent in the gastrocnemius muscle of male rat (p<0.05) . However, no significant sex difference in myosin ATPase activity was observed in three muscle examined in both age groups.<BR>4) Although not statistically significant, mean PFK activity was slightly lower in 35-week-old rats than in 10-week-old rats, and there was no sex difference in PFK activity at both weeks of age.<BR>5) SDH activity was significantly lower in 35-week-old rats than in 10-week-old rats except that there was no significant age difference in the gastrocnemius muscle of males. There was no significant sex difference in SDH activity in both age groups with an exception of the extensor digitorum longus muscle from 35-week-old rats, where males had significantly higher SDH activity than females.
RESUMO
1. The effect of thyroidectomy on histochemical properties of the extensor digitorum longus and soleus muscles was studied in rats. Two or 13 months after thyroidectomy animals were killed and muscle sections of 10μm thickness were stained for succinate dehydrogenase and myosin adenosine triphosphatase activities.<BR>2. No significant difference of the body weight was found between the thyroidectomized and sham-operated control groups. There was also no significant difference in the muscle weight between the two groups except that 13 months after thyroidectomy the soleus muscle weight was significantly lower in the thyroidectomized group than in the sham-operated control group.<BR>3. The measurement of muscle fiber diameter revealed that fast-twitch oxidative glycolytic fibers of the soleus muscle were smaller in the thyroidectomized group than in the sham-operated control group two or 13 months after thyroidectomy.<BR>4. The percentage of fast-twitch fibers decreased significantly after thyroidectomy with a concomitant increase in the percentage of slow-twitch fibers in both the extensor digitorum longus and soleus muscles. This finding suggests the involvement of thyroid hormone in determining a phenotypic expression of muscle fiber type.<BR>5. The results show that thyroidectomy-induced changes differ not only between the extensor digitorum longus and soleus muscles but also between same types of fibers from the two muscles. The results also indicate that thyroidectomy-induced changes depend on the period after thyroidectomy.