Cocaine and exercise: α-1 receptor blockade does not alter  muscle glycogenolysis or blood lactacidosis

In our previous work, we routinely observed that a combined cocaine-exercise challenge results in an abnormally rapid muscle glycogen depletion and excessive blood lactacidosis. These phenomena occur simultaneously with a rapid rise in norepinephrine and in the absence of any rise in epinephrine. We postulated that norepinephrine may cause vasoconstriction of the muscle vasculature through activation of α-1 receptors during cocaine-exercise, thus inducing hypoxia and a concomitant rise in glycogenolysis and lactate accumulation. To test this hypothesis, rats were pretreated with the selective α-1-receptor antagonist prazosin (P) (0.1 mg/kg iv) or saline (S). Ten minutes later, the animals were treated with cocaine (-C) (5 mg/kg iv) or saline (-S) and run for 4 or 15 min at 22 m/min at 10% grade. In the S-S group, glycogen content of the white vastus lateralis muscle was unaffected by exercise at both time intervals, whereas in S-C rats glycogen was reduced by 47%. This effect of cocaine-exercise challenge was not attenuated by P. Similarly, blood lactate concentration in S-C rats was threefold higher than that of S-S after exercise, a response also not altered by pretreatment with P. On the basis of these observations, we conclude that the excessive glycogenolysis and lactacidosis observed during cocaine-exercise challenge is not the result of vasoconstriction secondary to norepinephrine activation of α-1 receptors.

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Association Between Deoxygenated Hemoglobin Breaking Point, Anaerobic Threshold, and Rowing Performance

International Journal of Sports Physiology and Performance ◽

10.1123/ijspp.2018-0675 ◽

2019 ◽

Vol 14 (8) ◽

pp. 1103-1109

Author(s):

Tiago Turnes ◽

Rafael Penteado dos Santos ◽

Rafael Alves de Aguiar ◽

Thiago Loch ◽

Leonardo Trevisol Possamai ◽

...

Keyword(s):

Heart Rate ◽

Anaerobic Threshold ◽

Power Output ◽

Vastus Lateralis ◽

Lactate Concentration ◽

Blood Lactate Concentration ◽

Breaking Point ◽

Vastus Lateralis Muscle ◽

Incremental Test ◽

Deoxygenated Hemoglobin

Purpose: To compare the intensity and physiological responses of deoxygenated hemoglobin breaking point ([HHb]BP) and anaerobic threshold (AnT) during an incremental test and to verify their association with 2000-m rowing-ergometer performance in well-trained rowers. Methods: A total of 13 male rowers (mean [SD] age = 24 [11] y and = 63.7 [6.1] mL·kg−1·min−1) performed a step incremental test. Gas exchange, vastus lateralis [HHb], and blood lactate concentration were measured. Power output, , and heart rate of [HHb]BP and AnT were determined and compared with each other. A 2000-m test was performed in another visit. Results: No differences were found between [HHb]BP and AnT in the power output (236 [31] vs 234 [31] W; Δ = 0.7%), 95% confidence interval [CI] 6.7%), (4.2 [0.5] vs 4.3 [0.4] L·min−1; Δ = −0.8%, 95% CI 4.0%), or heart rate (180 [16] vs 182 [12] beats·min−1; Δ = −1.6%, 95% CI 2.1%); however, there was high typical error of estimate (TEE) and wide 95% limits of agreement (LoA) for power output (TEE 10.7%, LoA 54.1–50.6 W), (TEE 5.9%, LoA −0.57 to 0.63 L·min−1), and heart rate (TEE 2.4%, LoA −9.6 to 14.7 beats·min−1). Significant correlations were observed between [HHb]BP (r = .70) and AnT (r = .89) with 2000-m mean power. Conclusions: These results demonstrate a breaking point in [HHb] of the vastus lateralis muscle during the incremental test that is capable of distinguishing rowers with different performance levels. However, the high random error would compromise the use of [HHb]BP for training and testing in rowing.

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Diurnal Variation of Glycogen Content in Human Vastus Lateralis Muscle

Medicine & Science in Sports & Exercise ◽

10.1249/01.mss.0000495761.83363.14 ◽

2014 ◽

Vol 46 ◽

pp. 755

Author(s):

Hideyuki Takahashi ◽

Akiko Kamei ◽

Takuya Osawa ◽

Keisuke Shiose ◽

Takashi Kawahara ◽

...

Keyword(s):

Diurnal Variation ◽

Glycogen Content ◽

Vastus Lateralis ◽

Vastus Lateralis Muscle ◽

Lateralis Muscle

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Physiological responses to prolonged exercise in ultramarathon athletes

Journal of Applied Physiology ◽

10.1152/jappl.1986.61.2.611 ◽

1986 ◽

Vol 61 (2) ◽

pp. 611-617 ◽

Cited By ~ 58

Author(s):

C. T. Davies ◽

M. W. Thompson

Keyword(s):

Mechanical Properties ◽

Prolonged Exercise ◽

Glycogen Content ◽

Vastus Lateralis ◽

Physiological Responses ◽

Lactate Concentration ◽

Blood Lactate Concentration ◽

Intensity Level ◽

Mean Skin Temperature ◽

Sweat Loss

The physiological responses of 10 ultramarathon athletes to prolonged exercise at the highest intensity level they could sustain for 4 h have been examined. Energy expenditure for the 4 h of exercise was 14,146 +/- 1,789 kJ, of which 63% was provided by the oxidation of fat. Plasma free fatty acids rose, but the changes in blood lactate concentration (delta 0.2 mmol/l) and exchange ratio (delta 0.05) were small, and the postexercise glycogen content (130 +/- 42 mumol/g) of the vastus lateralis muscles was estimated to be 37–53% of normal resting values. During exercise O2 intake (VO2) increased with time from the 50th to 240th min, the rise becoming significant (P less than 0.01) after 110 min of work. The change in VO2 was equivalent to a rise in relative intensity (%VO2max) of +9.1% and a change of speed of 1.49 km/h. A rise in cardiac frequency compensated for a fall in stroke volume (SV), so that cardiac output was maintained, and the increases in rectal temperature (Tre) (delta 0.63 degree C) and sweat loss (3.49 +/- 0.50 kg, equivalent to 5.5% of body wt) and the decreased mean skin temperature (Tsk) (-1.22 degree C) were within tolerable limits during exercise. Following exercise there was a loss (-25%) of ability to generate voluntary force of the quadriceps femoris, though electrically evoked mechanical properties of the muscle remained unchanged. The results suggest that neither thermal nor cardiovascular factors are limiting to prolonged (4 h) exercise, although the ability to utilize fat as a fuel may be important in ultradistance athletes.(ABSTRACT TRUNCATED AT 250 WORDS)

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Oxidative capacity and glycogen content increase more in arm than leg muscle in sedentary women after intense training

Journal of Applied Physiology ◽

10.1152/japplphysiol.00101.2015 ◽

2015 ◽

Vol 119 (2) ◽

pp. 116-123 ◽

Cited By ~ 15

Author(s):

Nikolai B. Nordsborg ◽

Luke Connolly ◽

Pál Weihe ◽

Enzo Iuliano ◽

Peter Krustrup ◽

...

Keyword(s):

High Intensity ◽

Glycogen Content ◽

Citrate Synthase ◽

Vastus Lateralis ◽

High Volume ◽

Maximal Activity ◽

Vastus Lateralis Muscle ◽

Adaptive Potential ◽

Lateralis Muscle ◽

Sedentary Women

The hypothesis that the adaptive capacity is higher in human upper- than lower-body skeletal muscle was tested. Furthermore, the hypothesis that more pronounced adaptations in upper-body musculature can be achieved by “low-volume high-intensity” compared with “high-volume low-intensity” exercise training was evaluated. A group of sedentary premenopausal women aged 45 ± 6 yr (± SD) with expected high adaptive potential in both upper- and lower-extremity muscle groups participated. After random allocation to high-intensity swimming (HIS, n = 21), moderate-intensity swimming (MOS, n = 21), soccer (SOC, n = 21) or a nontraining control group (CON, n = 20), the training groups completed three workouts per week for 15 wk. Resting muscle biopsies were obtained from the vastus lateralis muscle and deltoideus muscle before and after the intervention. After the training intervention, a larger ( P < 0.05) increase existed in deltoideus muscle of the HIS group compared with vastus lateralis muscle of the SOC group for citrate synthase maximal activity (95 ± 89 vs. 27 ± 34%), citrate synthase protein expression (100 ± 29 vs. 31 ± 44%), 3-hydroxyacyl-CoA dehydrogenase maximal activity (35 ± 43 vs. 3 ± 25%), muscle glycogen content (63 ± 76 vs. 20 ± 51%), and expression of mitochondrial complex II, III, and IV. Additionally, HIS caused higher ( P < 0.05) increases than MOS in deltoideus muscle citrate synthase maximal activity, citrate synthase protein expression, and muscle glycogen content. In conclusion, the deltoideus muscle has a higher adaptive potential than the vastus lateralis muscle in sedentary women, and “high-intensity low-volume” training is a more efficient regime than “low-intensity high-volume” training for increasing the aerobic capacity of the deltoideus muscle.

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Determinants of endurance in well-trained cyclists

Journal of Applied Physiology ◽

10.1152/jappl.1988.64.6.2622 ◽

1988 ◽

Vol 64 (6) ◽

pp. 2622-2630 ◽

Cited By ~ 207

Author(s):

E. F. Coyle ◽

A. R. Coggan ◽

M. K. Hopper ◽

T. J. Walters

Keyword(s):

Blood Lactate ◽

Vastus Lateralis ◽

Lactate Concentration ◽

Blood Lactate Concentration ◽

Submaximal Exercise ◽

Vastus Lateralis Muscle ◽

Type I ◽

Vo2 Max ◽

Leg Extension ◽

Competitive Cyclists

Fourteen competitive cyclists who possessed a similar maximum O2 consumption (VO2 max; range, 4.6–5.0 l/min) were compared regarding blood lactate responses, glycogen usage, and endurance during submaximal exercise. Seven subjects reached their blood lactate threshold (LT) during exercise of a relatively low intensity (group L) (i.e., 65.8 +/- 1.7% VO2 max), whereas exercise of a relatively high intensity was required to elicit LT in the other seven men (group H) (i.e., 81.5 +/- 1.8% VO2 max; P less than 0.001). Time to fatigue during exercise at 88% of VO2 max was more than twofold longer in group H compared with group L (60.8 +/- 3.1 vs. 29.1 +/- 5.0 min; P less than 0.001). Over 92% of the variance in performance was related to the % VO2 max at LT and muscle capillary density. The vastus lateralis muscle of group L was stressed more than that of group H during submaximal cycling (i.e., 79% VO2 max), as reflected by more than a twofold greater (P less than 0.001) rate of glycogen utilization and blood lactate concentration. The quality of the vastus lateralis in groups H and L was similar regarding mitochondrial enzyme activity, whereas group H possessed a greater percentage of type I muscle fibers (66.7 +/- 5.2 vs. 46.9 +/- 3.8; P less than 0.01). The differing metabolic responses to submaximal exercise observed between the two groups appeared to be specific to the leg extension phase of cycling, since the blood lactate responses of the two groups were comparable during uphill running. These data indicate that endurance can vary greatly among individuals with an equal VO2 max.

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Glycogen Depletion of Human Skeletal Muscle Fibers in Response to High-Frequency Electrical Stimulation

Canadian Journal of Applied Physiology ◽

10.1139/h03-031 ◽

2003 ◽

Vol 28 (3) ◽

pp. 424-433 ◽

Cited By ~ 2

Author(s):

Michel J. Johnson ◽

Gilles Lortie ◽

Jean-Aimé Simoneau ◽

Marcel R. Boulay

Keyword(s):

Electrical Stimulation ◽

High Frequency ◽

Human Skeletal Muscle ◽

Glycogen Content ◽

Isometric Force ◽

Vastus Lateralis ◽

Muscle Fibres ◽

Vastus Lateralis Muscle ◽

Type I ◽

Lateralis Muscle

The purpose of the present study was to evaluate the pattern of change in muscular glycogen content in response to high-frequency electrical stimulation (HFES). Muscle biopsies were taken from the vastus lateralis muscle of 7 healthy young men before, 15 min after, and 30 min after electrical stimulation delivered at a 50-Hz frequency (15 s on, 45 s off) at an intensity of 100 mA. The glycogen content of type I, IIA, and IIB muscle fibres was evaluated using microphotometry of periodic acid Schiff (PAS) stained fibres. After 15 min of electrical stimulation, the glycogen content in type I, IIA, and IIB muscle fibres significantly decreased from 113 ± 10 (mean ± SE) to 103 ± 10 (p ≤ 0.05), 129 ± 9 to 102 ± 12 (p ≤ 0.01), and 118 ± 8 to 90 ± 13 (p ≤ 0.01) arbitrary relative units, respectively. No further decrement in glycogen content was observed in all three fibre types following an additional 15 min of HFES. In addition, isometric force decreased by approximately 50%, from 125.9 ± 20.0 N to 64.2 ± 7.7 N (p ≤ 0.01), during the first 15 contractions. No further decrease in isometric force was observed following an additional 15 contractions of HFES. These results reveal that significant reductions in isometric force of knee extensor muscles and glycogen content of all human skeletal muscle fibre types in vastus lateralis muscle are observable after 15 min of neuromuscular high-frequency transcutaneous electrical stimulation. Key words: energy metabolism, isometric strength

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Ayurvedic management of Myositis Ossificans of Vastus Lateralis Muscle (Urusthamba) - A Case Study

Journal of Ayurveda and Integrated Medical Sciences (JAIMS) ◽

10.21760/jaims.v2i1.7523 ◽

2017 ◽

Vol 2 (1) ◽

Author(s):

Vishnu Mohan ◽

Gopikrishna BJ ◽

Avnish Pathak ◽

Mahesh Kumar ES ◽

Duradundi G

Keyword(s):

Heterotopic Ossification ◽

Myositis Ossificans ◽

Vastus Lateralis ◽

Treatment Protocol ◽

Vastus Lateralis Muscle ◽

Satisfactory Treatment ◽

Lateralis Muscle ◽

Ayurvedic Treatment

Myositis ossificansis characterized by heterotopic ossification (calcification) of muscle of various etiologies. It is most commonly affected in the quadriceps of the thighs. There are many tools available for diagnosis of Myositis ossificans, but lack of satisfactory treatment. So the development of a treatment protocol for Myositis ossificans is the need of today`s era. In Ayurveda, the same can be understood as Urusthamba. The present paper discusses a case of Myositis ossificans of right vastus lateralis muscle and its Ayurvedic treatment.

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