Fluid intake, hydration status and body mass changes in U-15 judo athletes during a training day

Despite numerous studies related to dehydration there is still a lack of scientific literature presenting hydration status and fluid intake of judo athletes during different periods. Therefore, the aim of this study was to investigate, fluid intake, hydration status and body weight changes of young judo athletes during a typical day of training in preparation period. Twenty-two young judo athletes (age: 12 ± 0.7 y, experience: 3.5 ± 1.1) voluntarily participated in this study. Hydration status and weight were examined in the morning, before and immediately after the training. All athletes trained 90 min and they consumed fluids ad libitum during the exercise. According to morning urine specific gravity (USG) values, 81.2% of the athletes were dehydrated while only 18.8% of the athletes were euhydrated. Pre-training urine measurements showed that 63.64% of the athletes presented dehydration and 77.27% of the athletes completed the training in dehydrated condition despite fluid availability during the training. Mean body weight loss during training was -0.64 ± 0.66%. It can be concluded that young judo athletes presented high prevalence of dehydration as indicated by USG values. Most of the athletes were dehydrated during a typical training day and completed the training in more dehydrated conditions compared to pre training values despite ad libitum fluid intake. It is of great importance to evaluate hydration status of the athletes before training to refrain from common practice of fluid restriction for weight loss and adverse effects of a persistent state of fluid deficit on physical and health related state.

Urolitiasis en el niño / Urolithiasis in the child

La litiasis del tracto urinario es una condición que, por lo general, se asocia a alteraciones metabólicas como hipercalciuria, hipocitraturia, hiperfosfaturia, hiperuricosuria, hiperoxaluria, cistinuria y defecto de acidificación urinaria, pero su etiología es multifactorial, e intervienen en su formación la predisposición genética y los factores ambientales, entre los que la dieta y la baja ingestión de líquidos contribuyen a la formación de los cálculos. En niños y adolescentes las causas genéticas y anatómicas son las principales. La hipercalciuria idiopática es la causa más frecuente en estos grupos etarios, aunque, como en el adulto, los factores ambientales (ingestión dietética de sal, proteínas, calcio y otros nutrientes) pueden ganar importancia para su incremento. Entre los factores locales de la orina que favorecen la formación del cálculo se encuentran, la disminución del volumen urinario, el pH urinario bajo, la tendencia al estancamiento y las infecciones. En esta revisión se analizan brevemente las distintas causas que pueden producir litiasis, valorando la importancia de la ingestión adecuada de líquidos en general, las modificaciones dietéticas que deben realizarse en cada tipo de enfermedad litiásica, las diferentes medidas terapéuticas que deben utilizarse en el cólico nefrítico producido por litiasis, en los casos asintomáticos con litiasis demostrada y en los casos en que la litiasis pueda provocar obstrucción al flujo urinario

Urinary tract litiasis is a condition that is generally associated to metabolic impairments such as hypercalciuria, hypocitraturia, hyperphosphaturia, hyperuricosuria, hyperoxaluria, cystinuria and urinary acidification defect. However the true etiology of the disease is multifactoral and its formation involves genetic predisposition and environmental factors among which diet and low fluid intake contribute to the formation of calculi. The genetic and anatomic causes are the main factors in children and adolescents. Idiopathic hypercalciuria is the most frequent cause in these age groups, although as it occurs in the adult, the environmental factors (diet salt, protein, calcium and other nutrient intake) may be important for the disease. Among the local factors of the urine that may favor the formation of calculi are low urinary volume, low urinary pH, urinary retention and infections. This review briefly analyzed the various causes of lithiasis and assessed the importance of adequate fluid intake, the changes in diet that can be made according to the type of lithiasis, the different therapeutic actions that should be taken in case of lithiasis-caused renal colic, asymptomatic cases with proven lithiasis and in those cases in which lithiasis may obstruct urinary flow

Effect of L-5-Hydroxytryptophan on drinking behavior in Coturnix japonica (Temminck and Schlegel, 1849) (Galliformes: Aves): involvement of renin-angiotensin system

The purpose of this study was to explore the role of L-5-hydroxytryptophan (L-HTP) and its relationship with the renin-angiotensin system (RAS) on the drinking behavior in Japanese quails. Normally-hydrated quails that received injections of L-HTP (12.5; 25 and 50 mg.kg-1) by the intracoelomic route (ic) expressed an increase in water intake, which was inhibited by captopril, an angiotensin converting enzyme (ACE) inhibitor. In addition, captopril also induced such a response in birds under previous fluid deprivation. High doses of captopril (35-70 mg.kg-1, sc) in normally-hydrated quails decreased the spontaneous water intake while low doses of captopril (2-5 mg.kg-1, sc) did not prompt water intake after L-HTP administration. Losartan, an AT1 receptor antagonist in mammals, did not change the water intake levels in normally-hydrated or water-deprivated birds. Serotonin (5-HT) injections did not provoke its known dipsogenic response.

O objetivo deste estudo foi investigar a influência do L-5-hidroxitriptofano (L-HTP) e sua relação com o sistema renina-angiotensina (SRA) no comportamento dipsogênico de codornas. Codornas normohidratadas que receberam L-HTP em diferentes doses (12,5; 25 e 50 mg.kg-1) por via intracelomática (ic) expressaram um aumento na ingestão de água, o qual foi suprimido pela administração prévia de captopril (inibidor da ECA-enzima conversora de angiotensina). Esta ação inibitória do captopril, em menor intensidade, foi também evidenciada em aves previamente submetidas ao jejum hídrico. O tratamento isolado com captopril (35-70 mg.kg-1) reduziu consideravelmente a ingestão espontânea de água em codornas normohidratadas, enquanto baixas doses (2-5 mg.kg-1) não provocaram aumento na ingestão de água induzida pelo L-HTP. Losartan, um antagonista de receptores AT1 em mamíferos, não foi capaz de modificar os níveis de ingestão hídrica, tanto em aves normohidratadas quanto em aves privadas de água. Serotonina aplicada perifericamente não promoveu a conhecida resposta dipsogênica de mamíferos.

Water deprivation and the double- depletion hypothesis: common neural mechanisms underlie thirst and salt appetite

Water deprivation-induced thirst is explained by the double-depletion hypothesis, which predicts that dehydration of the two major body fluid compartments, the extracellular and intracellular compartments, activates signals that combine centrally to induce water intake. However, sodium appetite is also elicited by water deprivation. In this brief review, we stress the importance of the water-depletion and partial extracellular fluid-repletion protocol which permits the distinction between sodium appetite and thirst. Consistent enhancement or a de novo production of sodium intake induced by deactivation of inhibitory nuclei (e.g., lateral parabrachial nucleus) or hormones (oxytocin, atrial natriuretic peptide), in water-deprived, extracellular-dehydrated or, contrary to tradition, intracellular-dehydrated rats, suggests that sodium appetite and thirst share more mechanisms than previously thought. Water deprivation has physiological and health effects in humans that might be related to the salt craving shown by our species.

Impact of coffee and other selected factors on general mortality and mortality due to cardiovascular disease in Croatia.

In Croatia, the mortality rate is higher than that in the countries of the European Union (EU), and consumption of coffee is moderate compared to the EU countries. The study examined the effects of coffee consumption on all-cause (general) mortality, mortality due to cardiovascular disease, and survival. Analyses were based on data obtained from an epidemiological longitudinal study started in 1969 with follow-ups in 1972, including 1,571 men and 1,793 women aged 35-59 years, and in 1982, including 1,093 men and 1,330 women. The sample was age- and gender-stratified and included urban and rural populations from three coastal and three continental regions of Croatia. During the observation period from spring 1972 to the end of 1999, 568 men and 382 women died. In total, 254 men and 181 women died due to cardiovascular disease. The sample was classified in 4 groups: non-drinkers, consumption of coffee sometimes, regularly 1-2 cup(s), and regularly more than 2 cups per day. Apart from coffee, the effects of diastolic blood pressure, smoking habit, well-being, stomach ulcer, and resident status were analyzed. Data on general mortality and mortality due to cardiovascular disease were also analyzed. The influence of region and the effects of diastolic pressure and smoking habit on general mortality and cardiovascular disease-associated mortality were confirmed in both the sexes. No significant effects of coffee consumption on general mortality and mortality due to cardiovascular disease were found among men. Positive effects of coffee on general mortality (p = 0.0089) but not on cardiovascular disease-associated mortality were observed among women. Women who regularly drank coffee 1-2 cup(s) per day had a significantly lower risk of all-cause death adjusted for age, region, smoking, diastolic blood pressure, feeling of well-being, and history of stomach ulcer (relative risk = 0.631; p = 0.0033; confidence interval: 0.464-0.857). The role of coffee consumption on mortality was less relevant than other variables. However, it cannot be completely neglected in women.

Behavioral correlates of the activity of serotonergic and non-serotonergic neurons in caudal raphe nuclei

We investigated the behavioral correlates of the activity of serotonergic and non-serotonergic neurons in the nucleus raphe pallidus (NRP) and nucleus raphe obscurus (NRO) of unanesthetized and unrestrained cats. The animals were implanted with electrodes for recording single unit activity, parietal oscillographic activity, and splenius, digastric and masseter electromyographic activities. They were tested along the waking-sleep cycle, during sensory stimulation and during drinking behavior. The discharge of the serotonergic neurons decreased progressively from quiet waking to slow wave sleep and to fast wave sleep. Ten different patterns of relative discharge across the three states were observed for the non-serotonergic neurons. Several non-serotonergic neurons showed cyclic discharge fluctuations related to respiration during one, two or all three states. While serotonergic neurons were usually unresponsive to the sensory stimuli used, many non-serotonergic neurons responded to these stimuli. Several non-serotonergic neurons showed a phasic relationship with splenius muscle activity during auditory stimulation. One serotonergic neuron showed a tonic relationship with digastric muscle activity during drinking behavior. A few non-serotonergic neurons exhibited a tonic relationship with digastric and/or masseter muscle activity during this behavior. Many non-serotonergic neurons exhibited a phasic relationship with these muscle activities, also during this behavior. These results suggest that the serotonergic neurons in the NRP and NRO constitute a relatively homogeneous population from a functional point of view, while the non-serotonergic neurons form groups with considerable functional specificity. The data support the idea that the NRP and NRO are implicated in the control of somatic motor output

Estudo do comportamento motor decorrente da ingestäo de leite, em fetos de ratos: revisäo de literatura / Study of the motor behavior decurrent of the ingestion of milk in rat fetuses: review of literature

Nesta revisäo, focou-se os comportamentos motores e respostas fisiológicas de animais neonatos, associados com a ingestäo ou infusäo de leite, estudados em experimentos expressivos. Os experimentos demonstraram que os comportamentos e respostas foram mediados por neurotransmissores liberados, simultaneamente, à estimulaçäo com leite. Os experimentos säo apresentados detalhadamente com o objetivo de fornecer ao leitor uma visäo clara do desenvolvimento atual dos processos experimentais dessa linha de pesquisa.

Circadian and ultradian rhythms of drinking behavior of albino rats maintained in constant darkness

The objetive of the present study was to investigate the circadian and the ultradian rhythms of drinking behavior in Wistar rats maintained under conditions of constant darkness. Six mature male rats (weighing 270-350 g) were exposed to light-dark 12:12-h cycles (LD 12:12, lights on at 12:00 h) for 35 days and then switched to constant darkness (DD) conditions for at least 2 weeks. Drinking behavior was monitored continuously with a standard drinkometer circuit and the data were stored in 5-min bins. A modification of Enright's periodogram technique was used to evaluate the free-running drinking behavior circadin rhythm. Ultradian rhythms in drinking behavior were estimated by the Fast Fouries Transform (FFT) technique. Two of the animals (rats 4 and 6) showed no statistically significant circadian or ultradian rhythms and the other four showed free-running drinking circardian rhythm behavior shorter than 24 h (ranging from 23.333 to 23.967 h). Ultradian rhythms of drinking behavior of 12- and 8-h periods were detected in 4 (rats 1, 2, 3 and 5) and 2 (rats 1 and 5) animals, respectively. The relation of the compound structure of the circadian and ultradian rhythms is discussed demonstrating that drinking behavior is a good marker for studies of physiology of temporal organization.

Injection of ramipril into the lateral ventricle interferes with the drinking response induced by pharmacological and natural thirst stimuli

We investigated the effects of ramipril, an angiotensin I-converting enzyme (ACE) inhibitor, on water intake by male Holtzman rats (250-300 g) with cannulae implanted into the lateral ventricle. Intracerebroventricular (icv) injection of ramipril (1 µg/µl) significantly reduced drinking in response to subcutaneous (sc) injection of isoprenaline (100 µg/kg) from 8.49 + or - 0.69 to 2.96 + or - 0.36 ml/2 h, polyenthyleneglycol (PEG) (30 percent w/v, 10 ml/kg) from 9.51 + or - 2.20 to 1.6 + - 0.34 ml/2 h or water deprivation for 24 h from 12.61 + or - 0.83 to 5.10 + or - 1.37 ml/2 h. Ramipril had no effect on water intake induced by cellular dehydration produced by sc injection of hypertonic saline (2 M NaCl). These results are consistent with the hypothesis that ramipril acts as an ACE-blocking agent in the brain. The possibility that ramipril is transformed to ramiprilat, the active drug, by the brain is suggested

A study of action of norepinephrine on hypothalamic feeding centres.

Effects of intrahypothalamic and intraventricular microinjections of norepinephrine (NE) were studied in fasted albino rats. Applications of NE into ventromedial hypothalamus (VMH), medial part of lateral hypothalamus (LH) and lateral ventricle (LV) caused marked but short lasting decrease in food intake, whereas lateral part of LH was insensitive to NE administration. Decrease in water intake seemed secondary to decrease in food intake. Decrease in food intake could not be attributed to the alteration of body temperature. This study explains the mechanism of anorexigenic action of amphetamine and the mechanism of hyperphagia following destruction of the ventral noradrenergic bundle.

Central serotonergic modulation of drinking behavior induced by water deprivation: effect of a serotonergic agonist (MK-212) administered intracerebroventricularly

The present study was carried out to evaluate the participation of the serotonergic system (5-HT) in the modulation of the drinking response induced by water deprivation. Male Wistar rats implanted with a cannula in the 3rd ventricle were injected with the 5-HT1C/5-HT2 agonist 6-chloro-2-[1-piperazinyl]-pyrazine (MK-212) at doses of 0.5, 5, 25, 50 and 125 nmol/2 µl. MK-212 induced a significant reduction (p < ou = 0.05) in water intake over a period of 300 min. This result indicates that the central 5-HT system plays an important role, probably at the level of the periventricular hypothalamus, in the modulation of drinking behavior induced by water deprivation

Central serotonergic modulation of drinking behavior induced by angiotensin II and carbachol in normally hydrated rats: effect of intracerebroventricular injection of MK-212

The objective of the present study was to evaluate the role of the central erotonergic (5-HT) system in the modulation of drinking behavior induced angiotensin II (Ang II) and carbachol. Male Wistar rats implanted with a delay cannula in the 3 rd ventricle were injected with the 5-HT1C/5-HT2 agonist 6-chloro-2-[1-piperazinyl]-pyrazine (MK-212) (50 nmol/2 µl) before receiving an intracerebro-ventricular (icv) injection of Ang II or carbachol (100 ng/2 µl). MK-212 induced a significant reduction in the drinking response evoked by Ang II or carbachol which was more marked in the case of the cholinergic agonist. The results obtained suggest that thirst and water intake produced by angiotensinergic or cholinergic activation are modulated by the action of 5-HT, possibly at the level of the periventricular hypothalamus

Preferential saline or water intake by pinealectomized, adrenalectomized, and pinealectomized-adrenalectomized male rats

Because the pineal gland appears to be involved in the regulation of body electrolytes, saline or water preference was investigated imn pinealecrtomized, adrenalectomized, pinealectomized-adrenalectomized, and sham-operated (SO) control rats. The pinealectomized, adrenalectomized, and pinealectomized-adrenalectomized rats exhibites increased saline consumption during teh two postoperative weeks when compared with the SO-control animals. Water intake was similar for pinealectomized and SO-control rats, but decreased for pinealectomized-adrenalectomized, and adrenalectomized rats. Although total fluid intake increased for pinealectomized, and pinealectomized-adrenalectomized rats, the proportion of saline ingested in preference to water by pinealectomized-adrenalectomized rats was twice that exhibited by pinealectomized rats. The results showed two different behaviors: increased saline intake without changes in water intake by pinealectomized rats, and increased saline intake with decreased water intake by adrenalectomized rats. However, the higher salin intake induced by pinealectomy was further increased by adrenalectomy, suggesting a direct role for the pineal gland in meidating specific salt appetite

Effect of stress on behaviour in rats.

The pattern of activity obtained in rats on a regimen of one hour access to food and water was compared to the activity pattern seen when immobilization stress was added to the same regimen. Food and water were provided at the same time of the day. Immobilization stress decreased the body weight, increased the time taken for grooming, maintaining at the same time the food intake. The water intake also increased significantly but the alcohol intake was variable, 3 of the rats showing an increased intake while the rest showed a decreased intake under this stress regimen. The pattern of activity changed from hyper-activity during food restriction alone to increased activity restricted to the first half of the testing time during added immobilization.

Gustatory preferences during estrus cycle in rats.

Estrus cycle has been used as a base to study gustatory responses in rats under conditions of two-bottle choice test given for one hour daily, and the data pooled respectively for diestrus/metestrus (D/M) and proestrus/estrus (P/E). Glucose (13.5%), sodium saccharin (0.2%), sodium chloride (0.9%), citric acid (0.004%) and quinine sulphate (0.002%) was each paired with water and a particular solution was presented daily for one week. Two days gap was given between two different solutions when only water was made available in both the bottles. An increased preference for glucose and saccharin, decrease to sodium chloride and no change in citric acid and quinine sulphate was observed at P/E. The differential gustatory response is perhaps linked to the levels of ovarian and hypophyseal hormones at the time of ovulation.