Neuroendocrine and substrate responses to altered brain 5-HT activity during prolonged exercise to fatigue

1993 ◽  
Vol 74 (6) ◽  
pp. 3006-3012 ◽  
Author(s):  
S. P. Bailey ◽  
J. M. Davis ◽  
E. N. Ahlborn
Keyword(s):  
Prolonged Exercise ◽  
Plasma Free Fatty Acid ◽  
Liver Glycogen ◽  
Plasma Corticosterone ◽  
Treadmill Running ◽  
Time To Exhaustion ◽  
Lower Plasma ◽  
Brain Dopamine ◽  
Ly 53857 ◽  
General Plasma

Pharmacological manipulation of brain serotonergic [5-hydroxytryptamine (5-HT)] activity affects run time to exhaustion in the rat. These effects may be mediated by neurochemical, hormonal, or substrate mechanisms. Groups of rats were decapitated during rest, after 1 h of treadmill running (20 m/min, 5% grade), and at exhaustion. Immediately before exercise rats were injected intraperitoneally with 1 mg/kg of quipazine dimaleate (QD; a 5-HT agonist), 1.5 mg/kg of LY 53857 (LY; a 5-HT antagonist), or the vehicle (V; 0.9% saline). LY increased and QD decreased time to exhaustion (approximately 28 and 32%, respectively; P < 0.05). At fatigue, QD animals had greater plasma glucose, liver glycogen, and muscle glycogen concentrations but lower plasma free fatty acid concentration than did V and LY animals (P < 0.05). In general, plasma corticosterone and catecholamine levels during exercise in QD and LY rats were similar to those in V rats. Brain 5-HT and 5-hydroxyindole-3-acetic acid concentrations were higher at 1 h of exercise than at rest (P < 0.05), and the latter increased even further at fatigue in the midbrain and striatum (P < 0.05). Brain dopamine (DA) and 3,4-dihydroxyphenylacetic acid (DOPAC) were higher at 1 h of exercise (P < 0.05) but were similar to resting levels at fatigue. QD appeared to block the increase in DA and DOPAC at 1 h of exercise, and LY prevented the decrease in DA and DOPAC at fatigue (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Glycogen resynthesis in leg muscles of rats during exercise

1984 ◽  
Vol 247 (5) ◽  
pp. R880-R883 ◽  
Author(s):  
S. H. Constable ◽  
J. C. Young ◽  
M. Higuchi ◽  
J. O. Holloszy
Keyword(s):  
Muscle Glycogen ◽  
Prolonged Exercise ◽  
Liver Glycogen ◽  
Treadmill Running ◽  
Moderate Intensity ◽  
Glycogen Depletion ◽  
Moderate Intensity Exercise ◽  
Glycogen Resynthesis ◽  
Leg Muscles ◽  
Insulin In Plasma

This study was undertaken to determine whether glycogen resynthesis can occur in glycogen-depleted muscles in response to glucose feeding during prolonged exercise. Rats were exercised for 40 min with a treadmill running program designed to deplete muscle glycogen. One group was studied immediately after the glycogen-depletion exercise. A second group was given 1 g glucose by stomach tube and exercised for an additional 90 min at a running speed of 22 m/min on a treadmill set at an 8 degree incline; they were given additional 1-g glucose feedings after 30 and 60 min of running. The initial 40-min run resulted in liver glycogen depletion, large decreases in plasma glucose and insulin concentrations, and a marked lowering of muscle glycogen. The glucose feedings resulted in greater than twofold increases in the concentrations of glucose and insulin in plasma, and of glycogen in leg muscles, during the 90 min of running. No repletion of liver glycogen occurred. These results provide evidence that glycogen resynthesis can occur in glycogen-depleted muscle despite continued moderate intensity exercise if sufficient glucose is made available.

Adrenal hormones and liver cAMP in exercising rats--different modes of anesthesia

1983 ◽  
Vol 55 (5) ◽  
pp. 1634-1636 ◽  
Author(s):  
W. W. Winder ◽  
E. O. Fuller ◽  
R. K. Conlee
Keyword(s):  
Blood Glucose ◽  
Stress Hormones ◽  
Plasma Catecholamines ◽  
Liver Glycogen ◽  
Plasma Corticosterone ◽  
Lower Plasma ◽  
Adrenal Hormones ◽  
Pentobarbital Sodium ◽  
Cervical Dislocation ◽  
Response To Exercise

We have compared five different modes of anesthesia (iv and ip pentobarbital sodium, ether, CO2, and cervical dislocation) with respect to their effects on liver glycogen, liver adenosine 3′,5′-cyclic monophosphate (cAMP), blood glucose and lactate, plasma corticosterone, norepinephrine, and epinephrine in resting rats and in rats run on a treadmill at 26 m/min for 30 min. Ether, CO2, and cervical dislocation were found to be unsuitable due to the marked elevation in plasma catecholamines seen in both resting and exercising rats. Injection of pentobarbital sodium ip required an average of 8 min before onset of surgical anesthesia as opposed to less than 5 s for iv pentobarbital. Exercising rats anesthetized with ip pentobarbital showed markedly lower plasma catecholamines compared with rats given iv pentobarbital. Hepatic cAMP increased in response to exercise in all groups except the ip pentobarbital group. This is most likely due to the long delay between the end of the exercise and freezing of the liver in the ip pentobarbital-anesthetized animals. We conclude that iv injection of pentobarbital is the most suitable method of anesthesia for obtaining accurate measurements of plasma stress hormones, substrates, and metabolites and of hepatic cAMP and glycogen in resting and exercising rats.

The Effects of Cold and Prostaglandin E1 on Lipid Mobilization in the Chicken

1971 ◽  
Vol 49 (5) ◽  
pp. 394-398 ◽  
Author(s):  
W. D. Wagner ◽  
R. A. Peterson ◽  
R. J. Cenedella
Keyword(s):  
Fatty Acid ◽  
Free Fatty Acid ◽  
Cold Exposure ◽  
Prostaglandin E1 ◽  
Plasma Free Fatty Acid ◽  
Prostaglandin E ◽  
Elevated Plasma ◽  
Lower Plasma ◽  
Lipid Mobilization ◽  
Plasma Ffa

Plasma free fatty acid (FFA) levels and the effects of prostaglandin E1 (PGE1) were studied in cold-acclimated and cold-exposed chickens and compared to controls. Chickens cold-acclimated at 4–7 or 8–11 °C for 4 weeks had significantly elevated plasma FFA when compared to the controls at 19–21 °C. Although PGE1 had no effect on the basal level of FFA of controls, a significantly lower plasma FFA was seen after injection of either 10 or 30 μg PGE1/kg in cold-acclimated chickens. Chickens cold-exposed to 2–3 °C for 4 h demonstrated significant elevations of plasma FFA when compared to controls. Only 30 μg PGE1/kg significantly depressed the plasma FFA in the cold-exposed birds. No inhibition of basal FFA release was seen in control animals. From these experiments, it is concluded that chickens mobilize FFA extensively under cold-exposure and that this stimulated lipolysis is inhibited by PGE1.

Adrenocortical function in aging exercise-trained rats

1977 ◽  
Vol 43 (5) ◽  
pp. 839-843 ◽  
Author(s):  
J. A. Severson ◽  
R. D. Fell ◽  
J. G. Tuig ◽  
D. R. Griffith
Keyword(s):  
Age Groups ◽  
Plasma Corticosterone ◽  
Treadmill Running ◽  
Adrenocortical Function ◽  
Elevated Plasma ◽  
Corticosterone Concentration ◽  
Relationship Of ◽  
The Relationship

Plasma corticosterone concentrations and in vitro adrenal secretion of corticosterone were determined in exercise-trained rats. Rats, 100, 200, and 300 days of age, were trained for a 10-wk period by treadmill running. Following the training program, rats were subjected to an acute bout of swimming. Acute swimming elevated plasma corticosterone concentrations in all age groups. At 170 days of age, the plasma corticosterone concentration following swimming was higher in exercise-trained rats than in controls. The opposite was true of acutely swum rats at 270 and 370 days of age. Acute swimming elevated the in vitro adrenal gland response to adrenocorticotropic hormone stimulation in control rats at all ages and in trained rats at 170 days of age. The in vivo relationship of epinephrine and the pituitary adrenal system is suggested as a mechanism which could have caused this response. The relationship of secretion rates to plasma corticosterone concentrations indicated that extra-adrenal mechanisms, such as decreased turnover, were also responsible for the elevated plasma corticosterone levels observed in response to acute swimming.

Consumption of açai (Euterpe oleraceaMart.) functional beverage reduces muscle stress and improves effort tolerance in elite athletes: a randomized controlled intervention study

2015 ◽  
Vol 40 (7) ◽  
pp. 725-733 ◽  
Author(s):  
Jacqueline Carvalho-Peixoto ◽  
Mirian Ribeiro Leite Moura ◽  
Felipe Amorim Cunha ◽  
Pablo Christiano B. Lollo ◽  
Walace David Monteiro ◽  
...  
Keyword(s):  
High Intensity ◽  
Perceived Exertion ◽  
Maximal Exercise ◽  
Metabolic Stress ◽  
Ergogenic Aid ◽  
Treadmill Running ◽  
Time To Exhaustion ◽  
Euterpe Oleracea ◽  
Exercise Tests ◽  
Cardiorespiratory Responses

The study analyzed the effect of an açai (Euterpe oleracea Mart.) functional beverage (AB) on muscle and oxidative stress markers, cardiorespiratory responses, perceived exertion, and time-to-exhaustion during maximal treadmill running. The beverage was developed as an ergogenic aid for athletes and contained 27.6 mg of anthocyanins per dose. Fourteen athletes performed 3 exercise tests: a ramp-incremental maximal exercise test and 2 maximal exercise bouts performed in 2 conditions (AB and without AB (control)) at 90% maximal oxygen uptake.Blood was collected at baseline and after maximal exercise in both conditions to determine biomarkers. AB increased time to exhaustion during short-term high-intensity exercise (mean difference: 69 s, 95% confidence interval = –296 s to 159 s, t = 2.2, p = 0.045), attenuating the metabolic stress induced by exercise (p < 0.05). AB also reduced perceived exertion and enhanced cardiorespiratory responses (p < 0.05). The AB may be a useful and practical ergogenic aid to enhance performance during high-intensity training.

Effect of menstrual cycle phase on carbohydrate supplementation during prolonged exercise to fatigue

2000 ◽  
Vol 88 (2) ◽  
pp. 690-697 ◽  
Author(s):  
Stephen P. Bailey ◽  
Cristine M. Zacher ◽  
Karen D. Mittleman
Keyword(s):  
Fatty Acids ◽  
Menstrual Cycle ◽  
Prolonged Exercise ◽  
Cycle Phase ◽  
Time To Exhaustion ◽  
Menstrual Cycle Phase ◽  
Exercise Time ◽  
Carbohydrate Supplementation ◽  
Plasma Tyrosine ◽  
Placebo Drink

The effects of menstrual cycle phase and carbohydrate (CHO) supplementation were investigated during prolonged exercise. Nine healthy, moderately trained women cycled at 70% peak O2 consumption until exhaustion. Two trials were completed during the follicular (Fol) and luteal (Lut) phases of the menstrual cycle. Subjects consumed 0.6 g CHO ⋅ kg body wt− 1 ⋅ h− 1(5 ml/kg of a 6% CHO solution every 30 min beginning at min 30 of exercise) or a placebo drink (Pl) during exercise. Time to exhaustion during CHO increased from Pl values ( P < 0.05) by 14.4 ± 8.5 (Fol) and 11.4 ± 7.1% (Lut); no differences were observed between menstrual cycle phases. CHO attenuated ( P < 0.05) the decrease in plasma glucose and insulin and the increase in plasma free fatty acids, tryptophan, epinephrine, and cortisol observed during Pl for both phases. Plasma alanine, glutamine, proline, and isoleucine were lower ( P < 0.05) in Lut than in Fol phase. CHO resulted in lower ( P < 0.05) plasma tyrosine, valine, leucine, isoleucine, and phenylalanine. These results indicate that the menstrual cycle phase does not alter the effects of CHO supplementation on performance and plasma levels of related substrates during prolonged exercise.

scholarly journals Acute administration of high doses of taurine does not substantially improve high-intensity running performance and the effect on maximal accumulated oxygen deficit is unclear

2016 ◽  
Vol 41 (5) ◽  
pp. 498-503 ◽  
Author(s):  
Fabio Milioni ◽  
Elvis de Souza Malta ◽  
Leandro George Spinola do Amaral Rocha ◽  
Camila Angélica Asahi Mesquita ◽  
Ellen Cristini de Freitas ◽  
...  
Keyword(s):  
Oxygen Uptake ◽  
Exercise Intensity ◽  
Maximal Oxygen Uptake ◽  
High Intensity ◽  
Treadmill Running ◽  
Oxygen Deficit ◽  
Time To Exhaustion ◽  
Acute Administration ◽  
Running Performance ◽  
Accumulated Oxygen Deficit

The aim of the present study was to investigate the effects of acute administration of taurine overload on time to exhaustion (TTE) of high-intensity running performance and alternative maximal accumulated oxygen deficit (MAODALT). The study design was a randomized, placebo-controlled, crossover design. Seventeen healthy male volunteers (age: 25 ± 6 years; maximal oxygen uptake: 50.5 ± 7.6 mL·kg−1·min−1) performed an incremental treadmill-running test until voluntary exhaustion to determine maximal oxygen uptake and exercise intensity at maximal oxygen uptake. Subsequently, participants completed randomly 2 bouts of supramaximal treadmill-running at 110% exercise intensity at maximal oxygen uptake until exhaustion (placebo (6 g dextrose) or taurine (6 g) supplementation), separated by 1 week. MAODALT was determined using a single supramaximal effort by summating the contribution of the phosphagen and glycolytic pathways. When comparing the results of the supramaximal trials (i.e., placebo and taurine conditions) no differences were observed for high-intensity running TTE (237.70 ± 66.00 and 277.30 ± 40.64 s; p = 0.44) and MAODALT (55.77 ± 8.22 and 55.06 ± 7.89 mL·kg−1; p = 0.61), which seem to indicate trivial and unclear differences using the magnitude-based inferences approach, respectively. In conclusion, acute 6 g taurine supplementation before exercise did not substantially improve high-intensity running performance and showed an unclear effect on MAODALT.

Effect of fasting on myocardial substrates in male and female rats

1988 ◽  
Vol 254 (4) ◽  
pp. C560-C563 ◽  
Author(s):  
D. A. Arnall ◽  
W. K. Palmer ◽  
W. C. Miller ◽  
L. B. Oscai
Keyword(s):  
Experimental Period ◽  
Plasma Free Fatty Acid ◽  
Liver Glycogen ◽  
Female Rats ◽  
Male Rats ◽  
Fasting Period ◽  
Male And Female ◽  
Male And Female Rats ◽  
Entire Experiment ◽  
Beta Hydroxybutyrate

Adult male and female rats were fasted for 1, 2, or 3 days to determine its effect on circulating and endogenous fuels available to the heart. Liver glycogen was depleted within the first 24 h of food restriction. Plasma glucose decreased approximately 2.5 mM in both sexes during the 3 days. Fasting significantly increased plasma beta-hydroxybutyrate to approximately the same level in female and male rats. Plasma free fatty acid (FFA) increased approximately 0.2 mM in both groups during the first 24 h without food and remained elevated over the next 2 days. FFA concentrations were higher in fed female than in fed male rats and remained significantly higher in female rats throughout the experimental period. Myocardial glycogen increased 64% during the first 2 days of fasting in the male rats and stayed elevated on the third day of fasting. In contrast, heart glycogen of female rats remained unchanged from an initial value of 3.13 mg/g throughout the 3-day fasting period. Endogenous triglyceride (TG) of male rats decreased from 2.14 +/- 0.09 to 1.41 +/- 0.21 mumol/g during the first 24 h without food and remained at that level during the second and third days. Heart TG in female rats fell progressively from 2.36 +/- 0.19 to 1.02 +/- 0.12 mumol/g during the fasting period. Cardiac FFA were higher in female than in male animals throughout the entire experiment. These data indicate that quantitative and qualitative metabolic differences exist between male and female rats stressed by fasting.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of maternal exercise on liver and skeletal muscle glycogen storage in pregnant rats

1991 ◽  
Vol 71 (3) ◽  
pp. 1015-1019 ◽  
Author(s):  
M. F. Mottola ◽  
P. D. Christopher
Keyword(s):  
Skeletal Muscle ◽  
Muscle Glycogen ◽  
Glycogen Content ◽  
Liver Glycogen ◽  
Glycogen Storage ◽  
Treadmill Running ◽  
Control Group ◽  
Skeletal Muscle Glycogen ◽  
Maternal Exercise ◽  
White Gastrocnemius

To examine the effects of maternal exercise on liver and skeletal muscle glycogen storage, female Sprague-Dawley rats were randomly divided into control, nonpregnant runner, pregnant nonrunning control, pregnant runner, and prepregnant exercised control groups. The exercise consisted of treadmill running at 30 m/min on a 10 degree incline for 60 min, 5 days/wk. Pregnancy alone, on day 20 of gestation, decreased maternal liver glycogen content and increased red and white gastrocnemius muscle glycogen storage above control values (P less than 0.05). In contrast, exercise in nonpregnant animals augmented liver glycogen storage and also increased red and white gastrocnemius glycogen content (P less than 0.05). By combining exercise and pregnancy, the decrease in liver glycogen storage in the pregnant nonexercised condition was prevented in the pregnant runner group and more glycogen was stored in both the red and white portions of the gastrocnemius than all other groups (P less than 0.05). Fetal body weight was greatest (P less than 0.05) in the pregnant runner group and lowest (P less than 0.05) in the prepregnant exercise control group. These results demonstrate that chronic maternal exercise may change maternal glycogen storage patterns in the liver and skeletal muscle with some alteration in fetal outcome.

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