The Role of Opioid Peptides in the Hormonal Responses to Acute Exercise in Man

1984 ◽  
Vol 67 (5) ◽  
pp. 483-491 ◽  
Author(s):  
A. Grossman ◽  
P. Bouloux ◽  
P. Price ◽  
P. L. Drury ◽  
K. S. L. Lam ◽  
...  

1. Opioid involvement in the physiological and hormonal responses to acute exercise was investigated in six normal male subjects. Each was exercised to 40% (mild exercise) and 80% (severe exercise) of his previously determined maximal oxygen consumption on two occasions, with and without an infusion of high-dose naloxone. The exercise task was a bicycle ergometer; mild and severe exercise were performed for 20 min each, followed by a recovery period. 2. Exercise produced the expected increases in heart rate, blood pressure, ventilation, tidal volume, respiratory rate, oxygen consumption and carbon dioxide production. After severe exercise, naloxone infusion increased ventilation from 94.8 ± 4.9 litres/min to 105.7 ± 5.0 litres/min (P<0.05), but had no effect on any of the other physiological variables. 3. Exercise-induced changes in several hormones and metabolites were noted, including elevations in circulating lactate, growth hormone (GH), prolactin, cortisol, luteinizing hormone (LH), follicle stimulating hormone (FSH), adrenaline, noradrenaline, plasma renin activity (PRA) and aldosterone. There was no change in plasma met-enkephalin. Naloxone infusion produced the expected increases in LH and cortisol, but also significantly enhanced the elevations in prolactin, adrenaline, noradrenaline, plasma renin activity and aldosterone (P<0.05). 4. Psychological questionnaires revealed minor mood changes after exercise, but no evidence was found for the suggested ‘high’ or euphoria of exercise. Effort was perceived as greater during the naloxone infusion than the saline infusion in every subject. 5. We conclude that endogenous opioids may be important in the control of ventilation and the perception of effort at high levels of power output, and may modulate the responses of circulating catecholamines and the renin-aldosterone system to acute physical stress.

1986 ◽  
Vol 250 (4) ◽  
pp. R633-R637
Author(s):  
J. E. Szilagyi ◽  
J. Chelly ◽  
M. F. Doursout

The influence of blockade of endogenous opioids on the release of renin due to partial renal arterial constriction was determined acutely and chronically in unilaterally nephrectomized dogs. In acute preparations changes in plasma renin activity, arterial blood pressure, and heart rate were determined after 15 min of 60% renal arterial constriction before and after administration of either a saline vehicle, the opiate antagonist naloxone (0.05 mg/kg), or morphine (2 mg/kg). Acute antagonism of endogenous opiates abolished the increase in plasma renin activity and mean arterial pressure associated with renal arterial constriction. Repeated renal arterial constrictions in saline- or morphine-treated animals did not alter the humoral or hemodynamic responses. In chronic preparations long-term naloxone infusion attenuated the development of renovascular hypertension and diminished the increase in plasma renin activity. These data suggest that endogenous opioid peptides are modulators in the control of renin release and may be important participants in the pathogenesis of hypertension.


1986 ◽  
Vol 111 (2) ◽  
pp. 252-257 ◽  
Author(s):  
K. S. L. Lam ◽  
A. Grossman ◽  
P. Bouloux ◽  
P. L. Drury ◽  
G. M. Besser

Abstract. The effect of naloxone on the neurohumoral responses to acute sympathetic stimulation by sustained hand-grip in normal man was investigated. Six normal males were studied fasting at 08.30 h, on two occasions at 7-day intervals, with each subject sustaining 30% of his maximal hand-grip on a hand dynamometer for 5 min. Naloxone (8 mg bolus) in 20 ml normal saline, or saline alone, was given 5 min before hand-grip in a randomised double-blind cross-over trial. Blood was sampled for plasma renin activity, serum aldosterone and plasma catecholamines. The study was repeated in the absence of hand-grip. Sustained hand-grip produced significant elevations in mean blood-pressure, circulating adrenaline, noradrenaline and aldosterone. Naloxone, which had no effect on basal catecholamines, plasma renin activity or aldosterone, significantly enhanced the responses in plasma adrenaline, plasma renin activity and serum aldosterone to hand-grip. The increments in blood pressure and noradrenaline were not affected. These results suggest that endogenous opioids modulate the response of the sympathoadrenal and renin-aldosterone systems to acute sympathetic stimulation by a mild stress in man.


1988 ◽  
Vol 75 (3) ◽  
pp. 293-300 ◽  
Author(s):  
Jan Staessen ◽  
Roberto Fiocchi ◽  
Roger Bouillon ◽  
Robert Fagard ◽  
Peter Hespel ◽  
...  

1. Physical effort involves, along with an increase in the plasma concentration of β-endorphin, profound adaptations of the circulation and the endocrine system. The effects of opioid antagonism on the responses of blood pressure, heart rate and several hormones to exercise were therefore studied in 10 normal men. They exercised in the supine position up to 33% and 66% of their maximal exercise capacity and received in a randomized double-blind cross-over protocol, either saline or naloxone (10 mg intravenously, followed by a continuous infusion of 10 mg/h). 2. Intra-arterial pressure and heart rate were continuously monitored, but were not affected by naloxone. 3. At rest, opioid antagonism produced a rise in plasma renin activity and in plasma adrenocorticotropin, Cortisol and aldosterone, but only the stimulation of the two adrenocortical hormones differed significantly from the control experiments; at rest naloxone also prevented the fall in plasma adrenaline, which occurred with saline infusion. Furthermore, the exercise-induced rises in plasma angiotensin II, aldosterone, Cortisol, noradrenaline and adrenaline were higher on naloxone than on saline, while a similar tendency was also present for the increases with exercise in plasma renin activity and plasma adrenocorticotropin. Neither at rest nor during exercise did opioid antagonism alter plasma lactate and glucose and serum insulin and growth hormone. 4. In conclusion, (1) endogenous opioids are not involved in the responses of blood pressure and heart rate to supine exercise; (2) at rest and during exercise, the endogenous opioids inhibit the secretion of adrenocorticotropin, aldosterone, Cortisol, noradrenaline and adrenaline; (3) they also inhibit the plasma renin-angiotensin II system indirectly via the catecholamines.


1975 ◽  
Vol 5 (1) ◽  
pp. 17-24 ◽  
Author(s):  
Stephen N. Hunyor ◽  
Andrew J. Zweifler ◽  
Lennart Hansson ◽  
M. Anthony Schork ◽  
Charles Ellis

1988 ◽  
Vol 254 (1) ◽  
pp. H72-H80 ◽  
Author(s):  
C. E. Rose ◽  
L. B. Latham ◽  
V. L. Brashers ◽  
K. Y. Rose ◽  
M. P. Sandridge ◽  
...  

The role of endogenous opioids in systemic and renal circulatory changes during combined acute hypoxemia and hypercapnic acidosis was evaluated in seven conscious female mongrel dogs in rigid sodium balance. Animals were studied 2 wk apart in separate protocols of combined acute hypoxemia (arterial O2 tension = 33 +/- 1 mmHg) and hypercapnic acidosis (arterial CO2 tension = 56 +/- 1 mmHg, pH = 7.19 +/- 0.01) of 40 min duration during 1) naloxone, 5 mg/kg iv bolus followed by an intravenous infusion of 5 mg.kg-1.h-1, and 2) vehicle (5% dextrose in water) alone. Systemic circulatory changes during the combined acute blood-gas derangement including increased mean arterial pressure, heart rate, and cardiac output and decreased total peripheral resistance were comparable between naloxone and vehicle treatments. However, in striking contrast to the brief fall in renal hemodynamic function during combined acute hypoxemia and hypercapnic acidosis with vehicle, naloxone administration during the combined acute blood-gas derangement resulted in a sustained decrease in effective renal plasma flow, glomerular filtration rate, and filtered sodium load and enhanced rise in circulating norepinephrine and epinephrine. Changes in plasma renin activity were comparable between vehicle and naloxone protocols except that plasma renin activity increased from the first to the second 20-min periods of combined hypoxemia and hypercapnic acidosis with naloxone. These observations suggest that endogenous opioids may contribute to preservation of renal hemodynamic function during acute blood-gas derangements, possibly through attenuation of sympathetic nervous system and renin-angiotension activation.


1971 ◽  
Vol 67 (1) ◽  
pp. 159-173
Author(s):  
A. Peytremann ◽  
R. Veyrat ◽  
A. F. Muller

ABSTRACT Variations in plasma renin activity and urinary aldosterone excretion were studied in normal subjects submitted to salt restriction and simultaneous inhibition of ACTH production with a new synthetic steroid, 6-dehydro-16-methylene hydrocortisone (STC 407). At a dose of 10 mg t. i. d. this preparation exerts an inhibitory effect on the pituitary comparable to that of 2 mg of dexamethasone. In subjects maintained on a restricted salt intake, STC 407 does not delay the establishment of an equilibrium in sodium balance. The increases in endogenous aldosterone production and in plasma renin activity are also similar to those seen in the control subjects. A possible mineralocorticoid effect of STC 407 can be excluded. Under identical experimental conditions, the administration of dexamethasone yielded results comparable to those obtained with STC 407.


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