Maximal exercise test is a useful method for physical capacity and oxygen consumption determination in streptozotocin-diabetic rats

Rodrigues, Bruno; Figueroa, Diego; Mostarda, Cristiano Teixeira; Heeren, Marcelo Velloso; Irigoyen, Maria-Cláudia; Angelis, Kátia De

doi:10.1186/1475-2840-6-38

Cited by 143 publications

(109 citation statements)

References 32 publications

(49 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…On the other hand, we cannot be sure this difference in ratios would be maintained as respiratory rates change in vivo, since accurate measurement would be difficult, and the ratio per se would be sensitive to factors beyond respiration, including ATP production, membrane potential, respiratory coupling, and substrate utilization. We do point out that whole body oxygen use is actually increased in insulindeficient diabetes as our data (see text under Animal characteristics) and other reports (1,25,29,31) indicate.…”

Section: Discussionmentioning

confidence: 58%

Mitochondrial superoxide and coenzyme Q in insulin-deficient rats: increased electron leak

Herlein

Fink²,

Henry³

et al. 2011

American Journal of Physiology-Regulatory, Integrative and Comp

View full text Add to dashboard Cite

Mitochondrial superoxide is important in the pathogeneses of diabetes and its complications. However, there is uncertainty regarding the intrinsic propensity of mitochondria to generate this radical. Studies to date suggest that superoxide production by mitochondria of insulin-sensitive target tissues of insulin-deficient rodents is reduced or unchanged. Moreover, little is known of the role of the Coenzyme Q (CoQ), whose semiquinone form reacts with molecular oxygen to generate superoxide. We measured reactive oxygen species (ROS) production, respiratory parameters, and CoQ content in mitochondria from gastrocnemius muscle of control and streptozotocin (STZ)-diabetic rats. CoQ content did not differ between mitochondria isolated from vehicle- or STZ-treated animals. CoQ also was unaffected by weight loss in the absence of diabetes (induced by caloric restriction). Under state 4 or state 3 conditions, both respiration and ROS release were reduced in diabetic mitochondria fueled with succinate, glutamate plus malate, or with all three substrates (continuous TCA cycle). However, H2O2 and directly measured superoxide production were substantially increased in gastrocnemius mitochondria of diabetic rats when expressed per unit oxygen consumed. On the basis of substrate and inhibitor effects, the mechanism involved multiple electron transport sites. More limited results using heart mitochondria were similar. ROS per unit respiration was greater in muscle mitochondria from diabetic compared with control rats during state 3, as well as state 4, while the reduction in ROS per unit respiration on transition to state 3 was less for diabetic mitochondria. In summary, ROS production is, in fact, increased in mitochondria from insulin-deficient muscle when considered relative to electron transport. This is evident on multiple energy substrates and in different respiratory states. CoQ is not reduced in diabetic mitochondria or with weight loss due to food restriction. The implications of these findings are discussed.

show abstract

Section: Discussionmentioning

confidence: 58%

Mitochondrial superoxide and coenzyme Q in insulin-deficient rats: increased electron leak

Herlein

Fink²,

Henry³

et al. 2011

American Journal of Physiology-Regulatory, Integrative and Comp

View full text Add to dashboard Cite

show abstract

“…Sedentary and trained groups underwent a maximal treadmill test (25,30). The tests were performed in weeks 1, 5, and 10 of exercise training to determine aerobic capacity and adequate exercise training intensity.…”

Section: Methodsmentioning

confidence: 99%

Preventive role of exercise training in autonomic, hemodynamic, and metabolic parameters in rats under high risk of metabolic syndrome development

Moraes‐Silva

Mostarda

Moreira

et al. 2013

Journal of Applied Physiology

Self Cite

View full text Add to dashboard Cite

Moraes-Silva IC, Mostarda C, Moreira ED, Silva KAS, dos Santos F, de Angelis K, Farah VMA V, Irigoyen MC. Preventive role of exercise training in autonomic, hemodynamic, and metabolic parameters in rats under high risk of metabolic syndrome development. J Appl Physiol 114: 786 -791, 2013. First published January 17, 2013 doi:10.1152/japplphysiol.00586.2012.-High fructose consumption contributes to metabolic syndrome incidence, whereas exercise training promotes several beneficial adaptations. In this study, we demonstrated the preventive role of exercise training in the metabolic syndrome derangements in a rat model. Wistar rats receiving fructose overload in drinking water (100 g/l) were concomitantly trained on a treadmill (FT) or kept sedentary (F) for 10 wk. Control rats treated with normal water were also submitted to exercise training (CT) or sedentarism (C). Metabolic evaluations consisted of the Lee index and glycemia and insulin tolerance test (kITT). Blood pressure (BP) was directly measured, whereas heart rate (HR) and BP variabilities were evaluated in time and frequency domains. Renal sympathetic nerve activity was also recorded. F rats presented significant alterations compared with all the other groups in insulin resistance (in mg·dl Ϫ1 ·min Ϫ1 : F: 3.4 Ϯ 0.2; C: 4.7 Ϯ 0.2; CT: 5.0 Ϯ 0.5 FT: 4.6 Ϯ 0.4), mean BP (in mmHG: F: 117 Ϯ 2; C: 100 Ϯ 2; CT: 98 Ϯ 2; FT: 105 Ϯ 2), and Lee index (in g/mm: F ϭ 0.31 Ϯ 0.001; C ϭ 0.29 Ϯ 0.001; CT ϭ 0.27 Ϯ 0.002; FT ϭ 0.28 Ϯ 0.002), confirming the metabolic syndrome diagnosis. Exercise training blunted all these derangements. Additionally, FS group presented autonomic dysfunction in relation to the others, as seen by an ϳ50% decrease in baroreflex sensitivity and 24% in HR variability, and increases in sympathovagal balance (140%) and in renal sympathetic nerve activity (45%). These impairments were not observed in FT group, as well as in C and CT. Correlation analysis showed that both Lee index and kITT were associated with vagal impairment caused by fructose. Therefore, exercise training plays a preventive role in both autonomic and hemodynamic alterations related to the excessive fructose consumption.fructose; exercise training; autonomic nervous system SEVERAL STUDIES HAVE SHOWN that poor eating habits and a large increase in fructose consumption in recent years has contributed to the epidemic of metabolic syndrome (2, 5). These unhealthy habits may result in physiological changes that contribute to a higher morbidity and mortality in humans (14). Among these changes, increase of blood pressure, plasma lipids, obesity, glucose intolerance, insulin resistance, and hyperinsulinemia are the most evident. Additionally, studies have shown an association between these factors as hyperinsulinemia and hypertension, in both humans and animals (10, 21, 36), indicating that once these alterations are present, the higher is the incidence of cardiovascular diseases.Autonomic nervous system dysfunction also accompanies these metabolic disturbances. Our research group has ...

show abstract

“…Sedentary and trained rats were submitted to a maximum treadmill test as described in detail in a previous study (20). Tests were performed at the beginning of the experiment and in the 4th and 8th weeks of the training protocol.…”

Section: Exercise Protocolsmentioning

confidence: 99%

Tonic and reflex cardiovascular autonomic control in trained-female rats

Sanches

Sartori

Jorge

et al. 2009

Braz J Med Biol Res

View full text Add to dashboard Cite

The effects of exercise training on cardiovascular and autonomic functions were investigated in female rats. After an aerobic exercise training period (treadmill: 5 days/week for 8 weeks), conscious female Wistar (2 to 3 months) sedentary (S, N = 7) or trained rats (T, N = 7) were cannulated for direct arterial pressure (AP) recording in the non-ovulatory phases. Vagal (VT) and sympathetic tonus (ST) were evaluated by vagal (atropine) and sympathetic (propranolol) blockade. Baroreflex sensitivity was evaluated by the heart rate responses induced by AP changes. Cardiopulmonary reflex was measured by the bradycardic and hypotensive responses to serotonin. Resting bradycardia was observed in T (332 ± 7 bpm) compared with S animals (357 ± 10 bpm), whereas AP did not differ between groups. T animals exhibited depressed VT and ST (32 ± 7 and 15 ± 4 bpm) compared to S animals (55 ± 5 and 39 ± 10 bpm). The baroreflex and cardiopulmonary bradycardic responses were lower in T (-1.01 ± 0.27 bpm/mmHg and -17 ± 6 bpm) than in the S group (-1.47 ± 0.3 bpm/mmHg and -41 ± 9 bpm). Significant correlations were observed between VT and baroreflex (r = -0.72) and cardiopulmonary (r = -0.76) bradycardic responses. These data show that exercise training in healthy female rats induced resting bradycardia that was probably due to a reduced cardiac ST. Additionally, trained female rats presented attenuated bradycardic responses to baro- and cardiopulmonary receptor stimulation that were associated, at least in part, with exercise training-induced cardiac vagal reduction

show abstract

Maximal exercise test is a useful method for physical capacity and oxygen consumption determination in streptozotocin-diabetic rats

Cited by 143 publications

References 32 publications

Mitochondrial superoxide and coenzyme Q in insulin-deficient rats: increased electron leak

Mitochondrial superoxide and coenzyme Q in insulin-deficient rats: increased electron leak

Preventive role of exercise training in autonomic, hemodynamic, and metabolic parameters in rats under high risk of metabolic syndrome development

Tonic and reflex cardiovascular autonomic control in trained-female rats

Contact Info

Product

Resources

About