Urinary dopamine in physical and mental effort

Dopamine in urine was investigated during three levels of physical stress (at 35%, 50%, and 75% VO2 max.) and three kinds of mental stress (delayed auditory feedback, vigilance task and arithmetic task). A statistically significant increase in excretion of dopamine was found in response to physical exercise and the delayed auditory feedback test. The response patterns (ratios noradrenaline/dopamine and adrenaline/dopamine) after physical and mental stress differed. The data presented support the possibility of using dopamine excretion and the above ratios to differentiate between mental and physical effort.     

Hormonal Neuroendocrine and Vasoconstrictor Peptide Responses of Ball Game and Cyclic Sport Elite Athletes by Treadmill Test

ObjectiveOur objective was to evaluate complex hormonal response in ball game and cyclic sport elite athletes through an incremental treadmill test, since, so far, variables in experimental procedures have often hampered comparisons of data.MethodsWe determined anthropometric data, heart rate, maximal oxygen uptake, workload, plasma levels of lactate, adrenaline, noradrenaline, dopamine, cortisol, angiontensinogen and endothelin in control (n = 6), soccer (n = 8), handball (n = 12), kayaking (n = 9) and triathlon (n = 9) groups based on a Bruce protocol through a maximal exercise type of spiroergometric test.ResultsWe obtained significant increases for adrenaline, 2.9- and 3.9-fold by comparing the normalized means for soccer players and kayakers and soccer players and triathletes after/before test, respectively. For noradrenaline, we observed an even stronger, three-time significant difference between each type of ball game and cyclic sport activity.ConclusionsExercise related adrenaline and noradrenaline changes were more pronounced than dopamine plasma level changes and revealed an opportunity to differentiate cyclic and ball game activities and control group upon these parameters. Normalization of concentration ratios of the monitored compounds by the corresponding maximal oxygen uptake reflected better the differences in the response level of adrenaline, noradrenaline, dopamine and cortisol.     

Evaluation of sympathoadrenal activity, adrenocortical function and androgenic status in five men during a Himalayan mountaineering expedition (ascent of Mt Pabil, 7,102 m, 23,294 ft)

Sympathoadrenal activity, adrenocortical function and androgenic status were studied in five well-trained mountaineers during the different phases of a mountaineering expedition during the ascent of Mt Pabil (7,102 m) in the Ganesh Himal massif. Sympathoadrenal activity was evaluated by measuring urinary excretion of adrenaline, noradrenaline, metanephrines, and vanillinmandelic acid. Adrenocortical function was assessed by measuring urinary excretion of free cortisol, 17 OHCS (17-hydroxycorticosteroids) and androgenic status by measuring testosterone glucuronide, Adiol (5 alpha-androstane-3 alpha, 17 beta diol) and 17KS (17-ketosteroids). Reference values were obtained at Chamonix at 1,037 m during rest. During trekking noradrenaline increased significantly while Adiol and 17-KS decreased. The fall in the urinary androgenic pool persisted during the next phases of the expedition. At base camp (4,800 m) noradrenaline, its metabolites and free cortisol increased mainly during physical activity. Above 6,000 m, adrenaline, noradrenaline, their metabolites, free cortisol and 17-OHCS reached a maximum value. During the return to sea level, the urinary level of these parameters was still high. The drop in the urinary androgenic pool observed during trekking and exposure to high altitude confirms results obtained in other studies on prolonged efforts. This hypoandrogenicity may play an important role in the metabolic adaptations as well as in the mental state of the climbers. The increase of sympathoadrenal activity and of adrenocortical function may be considered as a regulatory element in the adaptative response to hypoxia and other stressors proper to high altitude.     

Plasma testosterone and catecholamine responses to physical exercise of different intensities in men

Plasma testosterone, noradrenaline, and adrenaline concentrations during three bicycle ergometer tests of the same total work output (2160 J X kg-1) but different intensity and duration were measured in healthy male subjects. Tests A and B consisted of three consecutive exercise bouts, lasting 6 min each, of either increasing (1.5, 2.0, 2.5 W X kg-1) or constant (2.0, 2.0, 2.0 W X kg-1) work loads, respectively. In test C the subjects performed two exercise bouts each lasting 4.5 min, with work loads of 4.0 W X kg-1. All the exercise bouts were separated by 1-min periods of rest. Exercise B of constant low intensity resulted only in a small increase in plasma noradrenaline concentration. Exercise A of graded intensity caused an increase in both catecholamine levels, whereas, during the most intensive exercise C, significant elevations in plasma noradrenaline, adrenaline and testosterone concentrations occurred. A significant positive correlation was obtained between the mean value of plasma testosterone and that of adrenaline as well as noradrenaline during exercise. It is concluded that both plasma testosterone and catecholamine responses to physical effort depend more on work intensity than on work duration or total work output.     

Catecholamine release and interrenal response of brown trout, Salmo trutta, exposed to aluminium in acidic water

Cannulated brown trout, Salmo trutta , were exposed for 36 h to synthetic water with a low calcium content of pH 5 and similar synthetic water dosed with aluminium to raise the filterable A1 from 5 to 290 μg 1⁻¹ over the 36-h period. There were no significant disturbances of plasma concentrations of glucose, cortisol or catecholamine (adrenaline and noradrenaline) in fish held in water of pH 5. The addition of aluminium to this acidic synthetic water resulted in a generalized endocrine stress response with a four-fold increase in plasma glucose concentration after 18 h and a significant increase in plasma cortisol concentration from 24 h onwards when filterable A1 exceeded 200 μg 1⁻¹. Plasma catecholamine concentration indicated an adrenergic stress response in aluminium-exposed brown trout. A transient doubling in noradrenaline after 6 h in A1 was followed by a larger increase in both plasma adrenaline and noradrenaline concentrations in fish surviving the 36-h exposure to A1.     

The actions of some putative neurotransmitters on the cockroach salivary gland.

1. Certain putative transmitters were applied to the innervated cockroach salivary gland and their effects on the resting potential and the neurally evoked secretory potential of the acinar cells were observed. 2. gamma-Aminobutyric acid, glutamate, glycine, aspartate and alanine had no significant effect on the resting potential. However, gamma-aminobutyric acid and glutamate reduced the neurally evoked secretory potential but only at concentrations above 10(-3) M3. Acetylcholine and carbachol appeared to act by modifying transmitter output from the salivary nerves. These substances failed to have any effect on the resting potential. 4. The biogenic amines, adrenaline, dopamine, noradrenaline, 5-hydroxy-tryptamine and octopamine, produced hyperpolarizing responses, graded according to concentration. 5. It is suggested that dopamine, the most potent of the biogenic amines tested, is the transmitter at this junction.     

Short-term low-carbohydrate diet dissociates lactate and ammonia thresholds in men

A low-carbohydrate (L-CHO) diet has been shown to shift the lactate threshold toward higher workloads. The aim of the present study was to examine the effect of an L-CHO diet on the ammonia threshold and to compare it with the lactate threshold in men. The plasma catecholamine threshold was also measured. Eight young, untrained men participated in the study. Two exercise tests with graded workload were performed. The workload was increased every 3 minutes by 40 W until volitional exhaustion. The first test was performed after 3 days of a controlled mixed diet. After the first test, the mixed diet was switched to a L-CHO diet. Three days later the same test was repeated. The blood concentration of lactate, ammonia, noradrenaline, and adrenaline was measured before and after each workload in both groups. It was found that the concentration of the examined compounds in the blood increases exponentially with graded workload after each kind of diet. This led us to calculate the blood ammonia, lactate, epinephrine, and norepinephrine thresholds. The thresholds were defined as points at which the concentration of a given compound starts to increase in a nonlinear fashion, which is calculated using 2 segmental linear regressions. After the mixed diet, the threshold for each compound occurs at the same workload. The L-CHO diet resulted in dissociation of the lactate threshold from the ammonia threshold: the lactate threshold was shifted toward a higher workload, whereas the ammonia threshold was shifted toward a lower workload. The norepinephrine threshold was also shifted toward a lower workload, and the epinephrine threshold remained unchanged. The results obtained indicate that an L-CHO diet accelerates production of ammonia and delays production of lactate during graded exercise, as well as that diet must be strictly controlled when ammonia and lactate thresholds are measured.     

Urinary catecholamine responses to basic types of physical activity

Urinary adrenaline, noradrenaline, heart rate, and subjective ratings were obtained from 9 healthy males during six different physical activities, ranging in intensity from lying down to running. Heart rate, subjective ratings and noradrenaline excretion reflected the work load in the different conditions. Adrenaline, on the other hand, failed to show this relationship. There was no significant increase in adrenaline excretion even at the highest work load (corresponding to a heart rate of 160 bpm). It was concluded that urinary adrenaline may safely be used as an indicator of mental factors even in situations with different levels of physical activity.     

Capillary-venous differences of free plasma catecholamines at rest and during graded exercise

Levels of free plasma catecholamines were simultaneously determined in 10 cyclists using capillary blood from one ear lobe and venous blood from one cubital vein. Catecholamine concentrations were higher in the ear lobe blood than in the venous blood at rest and during graded exercise. Average differences amounted to 1.7 nmol X 1(-1) (dopamine), 2.1 nmol X 1(-1) (noradrenaline) and 1.9 nmol X 1(-1) (adrenaline) at rest and increased only to 8.8 nmol X 1(-1) for noradrenaline during exercise. We assume that higher concentrations of dopamine and adrenaline in the capillary blood point to a significant neuronal release of these catecholamines, similar to noradrenaline. Catecholamine concentrations in capillary blood may better reflect sympathetic drive and delivery of catecholamines to the circulation than the concentrations in venous blood.     

Caffeine Ingestion by Rats Increases Noradrenaline Turnover and Results in Self-Biting

The effects of caffeine on the activity of central and peripheral catecholaminergic structures have been studied in rats ingesting high doses of caffeine. The activities of the enzymes tyrosine hydroxylase and dopamine-beta-hydroxylase were measured as well as 3,4-dihydroxyphenylethylamine (dopamine), adrenaline, and noradrenaline concentrations, in brain (striatum and hypothalamus), heart, and adrenal gland. At the peripheral level, we observed a significant increase in the dopamine and adrenaline plus noradrenaline content in the heart, but an increase in dopamine content only was found in the adrenal gland. Dopamine-beta-hydroxylase activity in serum was increased, but the only significant enzymic change in brain was an increase in the dopamine-beta-hydroxylase activity of the hypothalamus. However, an increase in catecholamine content was observed in both structures of the brain. These data suggest that the mechanisms involved in caffeine-induced self-biting in rats are not limited to the dopaminergic system, because we have also observed an increase in noradrenaline turnover.     

Secretion of Dopa in Phaeochromocytoma

In a series of 11 cases with phaeochromocytoma, two patients were found in whom the tumour secreted dopa in addition to dopamine, noradrenaline, and adrenaline. These two patients were normotensive in spite of high plasma and urinary levels of noradrenaline and adrenaline. This raises the possibility that dopa may be able to protect against the hypertensive action of noradrenaline. Such a mechanism would also explain the absence of hypertension in many cases of neuroblastoma.     

Effects of pressure on the skin exerted by clothing on responses of urinary catecholamines and cortisol,heart rate and nocturnal urinary melatonin in humans

The study investigated how the pressure exerted on the skin by clothing worn while working in the daytime affected the urinary excretion of adrenaline, noradrenaline and cortisol, heart rate, and also melatonin secretion at night. Nine young women (experiment I) and seven young women (experiment II) participated. Participants wore either a 100% cotton jacket (tight clothes, TC) or a 100% cotton T-shirt (loose clothes, LC). Loose-fitting, 100% cotton tank tops and panties were worn as underwear in both the TC and the LC groups. The main results can be summarized as follows: (1) urinary excretion of adrenaline, noradrenaline and cortisol was facilitated, and the amounts of urinary excretion were significantly higher when TC were worn. Heart rate was significantly higher in the TC group; (2) nocturnal urinary melatonin excretion was significantly greater in the TC group. These results are discussed in terms of an enhancement of diurnal sympathetic nervous system activity caused by pressure on the skin produced by tight clothing.     

Plasma catecholamines in man are not influenced by the inhibition of prostaglandin synthesis.

Indomethacin has been reported to potentiate the release of noradrenaline from sympathetic nerve endings in vitro and to increase urinary noradrenaline excretion in rats. We have studied the influence of indomethacin on plasma catecholamine levels in 10 normal men, using measurement of plasma renin activity (PRA) as an index of the pharmacodynamic effect of indomethacin. Both in the supine and standing positions indomethacin failed to alter the plasma concentrations of noradrenaline, adrenaline or dopamine, while PRA was markedly suppressed. It is concluded that in the intact human indomethacin does not influence catecholamine concentrations.     

Effect of a fall of blood pressure on the release of catecholamines in the hypothalamus

The posterior hypothalamus of anaesthetized cats was superfused through a push-pull cannula and the release of endogenous catecholamines was determined in the superfusate which was continuously collected in 15 min periods. Fall in blood pressure elicited by nitroprusside or bleeding led to an increased rate of release of noradrenaline, adrenaline and dopamine in the hypothalamus. Transection of the brain causal to hypothalamus greatly reduced the rate of resting release of the catecholamines and abolished the enhancing effects of bleeding and nitroprusside. Determination of the catecholamines in samples which were collected in 90 s periods suggested a different pattern of release of the three catecholamines. Further shortening of the collection period (10 s) showed that the fall in blood pressure immediately increased the release of dopamine, while the rates of release of noradrenaline and adrenaline were increased gradually. Hypotension did not influence the rates of release of the catecholamines in the anterior hypothalamus. It is concluded that dopamine, adrenaline and noradrenaline systems of the hypothalamus are involved in the regulation of the arterial blood pressure. The different patterns of release might indicate that dopamine exerts a different function from those of noradrenaline and adrenaline in the normalization of the blood pressure after acute hypotension.     

Metabolic response to insulin induced hypoglycaemia in lean and obese subjects

Metabolic response to insulin induced hypoglycaemia was examined in 8 lean and 11 obese subjects. The metabolic rate increased in lean and obese subjects during the hypoglycaemia. The mean response (as the sum of all the values above basal) was not significantly different between lean and obese subjects. The mean decrease in blood glucose and the mean hormonal response (increase in cortisol, adrenaline and noradrenaline) were not different between lean subjects and obese subjects. However, the metabolic response and noradrenaline response were variable in obese subjects and some obese subjects showed a poor response. These results suggest that in some obese subjects, there may be reduced thermogenic response to insulin induced hypoglycaemia.     

Catecholamine levels in whole brain of stressed and control domestic and wild rats (Rattus Norvegicus)

Whole brain catecholamine (dopamine, nonadrenaline, adrenaline) levels were measured in control and electric footshocked Wild and domestic (Sprague Dawley and Long Evans) rats. No significant differences were found among the three strains of rats for combined total catecholamine content, or for combined total catecholamines between the control and footshocked groups. Significant differences were found for the total of each catecholamine taken separately, dopamine being present at three times the level of noradrenaline and ten times the level of adrenaline. No significant differences were found for dopamine in both control and footshocked animals among all three rat strains. Noradrenaline was significantly higher in the control domestic rats compared to the control Wild rats, and in the footshocked domestic rats compared to the footshocked Wild rats. No differences in noradrenaline levels were found between Sprague Dawley and Long Evans rats, but noradrenaline increased significantly in the latter following footshock. Adrenaline was significantly highest in the Sprague Dawley controls and lowest in the Wild controls. Footshocking resulted in almost identical levels of adrenaline in the domestic strains and an increase in the F₁ Wild strain.     

Plasma catecholamines in man are not influenced by the inhibition of prostaglandin synthesis

Indomethacin has been reported to potentiate the release of noradrenaline from sympathetic nerve endings $\text{in vitro}$ and to increase urinary noradrenaline excretion in rats. We have studied the influence of indomethacin on plasma catecholamine levels in 10 normal men, using measurement of plasma renin activity (PRA) as an index of the pharmacodynamic effect of indomethacin. Both in the supine and standing positions indomethacin failed to alter the plasma concentrations of noradrenaline, adrenaline or dopamine, while PRA was markedly suppressed. It is concluded that in the intact human indomethacin does not influence catecholamine concentrations.     

Lack of Selectivity Between the Uptake of [3H] Adrenaline and [3H]Noradrenaline into Rat Hypothalamic Slices

The uptake of [3H]adrenaline and [3H]noradrenaline into rat hypothalamic slices was compared for determination of whether adrenaline uptake was independent of uptake into noradrenergic neurones. Kinetic analysis revealed a similar high-affinity uptake process for both adrenaline and noradrenaline, with Km and Vmax values within similar ranges. These uptakes were inhibited by desipramine and maprotiline in a dose-dependent manner, but the selective dopamine and 5-hydroxytryptamine uptake inhibitors benztropine and fluoxetine, respectively, were without effect. Competition for uptake sites by unlabelled adrenaline with [3H]adrenaline and [3H]-noradrenaline and by unlabelled noradrenaline with [3H]-adrenaline and [3H]noradrenaline was very similar. Lesioning of the major adrenaline-containing cell group (C1 cell group) decreased the hypothalamic adrenaline concentration but had no effect on hypothalamic [3H]adrenaline or [3H]noradrenaline uptake. The results suggest that exogenous adrenaline is largely taken up by high-affinity sites on noradrenergic nerve terminals.     

Urinary dopamine, noradrenaline and adrenaline in type 2 diabetic patients with and without nephropathy

We measured the urinary excretions of dopamine, noradrenaline and adrenaline, their conjugated metabolites, urinary excretion of sodium and creatinine clearance simultaneously in 21 patients with Type 2 (non-insulin-dependent) diabetes and 6 normal subjects. The mean (+/- SEM) value for urinary excretion of dopamine (52.4 +/- 8.8 micrograms/day) in diabetic patients with nephropathy (Group C, n = 12) was significantly lower (P less than 0.01) than in the normal subjects (Group A, 179.7 +/- 15.5 micrograms/day) and in diabetic patients without nephropathy (Group B, n = 9, 131.5 +/- 16.5 micrograms/day). The mean values for the urinary excretions of noradrenaline and adrenaline were also significantly lower (P less than 0.01) in Group C than in Groups A and B. In addition, the mean urinary excretion of conjugated metabolite of dopamine in Group C was significantly lower (P less than 0.05) than in Group A. There was a trend toward the observation that the mean 24-h urinary excretion of sodium in Group C (121.6 less than 12.9 mEq) was lower as compared with that in Group A (140.8 +/- 8.9 mEq) or B (150.7 +/- 17.9 mEq). A multiple regression analysis revealed that the 24-h urinary excretion of dopamine correlated significantly with creatinine clearance, systolic (P less than 0.01) and diastolic (P less than 0.05) blood pressures. The results indicate that synthesis or secretion of renal dopamine might decrease with a progression of diabetic nephropathy.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of restraint stress on catecholamine concentrations in the glandular stomach of rats

Restraint stress is known to induce gastric ulcers in rats. Peripheral sympathetic activity and catecholamines are involved in the pathogenesis of these gastric ulcers. The aim of the present study was to evaluate the effects of restraint on mucosal and muscle catecholamine concentrations in the glandular stomach of rats. In unrestrained rats, noradrenaline concentration was higher in the muscle than in the mucosa of the glandular stomach (629 +/- 106 vs 18 +/- 3 pg/mg and 217 +/- 37 vs 18 +/- 8 pg/mg, respectively in the corpus and the antrum, p less than 0.01). This can be explained by the existence of an abundant noradrenergic innervation in the muscle layer. After 20 hours of restraint, adrenaline and noradrenaline concentrations were significantly decreased in adrenals, in comparison with unrestrained animals (255 +/- 53 vs 638 +/- 160 ng/mg and 113 +/- 17 vs 198 +/- 37 ng/mg, respectively for adrenaline and noradrenaline, p less than 0.05). In the glandular stomach, noradrenaline and adrenaline concentrations in restrained rats were not significantly different from those in unrestrained rats. However, adrenaline concentrations in the muscle of restrained rats were higher than in the mucosa. Moreover, restraint induced a significant decrease in dopamine concentration in the antral mucosa (from 100 +/- 12 pg/mg in unrestrained rats to 15 +/- 5 pg/mg in restrained rats), suggesting that a depletion in dopamine in the antral mucosa could be one of the pathogenetic factors involved in antral gastric stress-induced ulcers in rats.