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Background Water balance is achieved when water intake from solid and fluid foods and drinking water meets water losses, mainly in sweat, urine and faeces. Seasonality, particularly in Mediterranean countries that have a hot summer, may affect water loss and consequently water balance. Water balance has not been estimated before on a population level and the effect of seasonality has not been evaluated. The present study aimed to compare water balance, intake and loss in summer and winter in a sample of the general population in Greece. Methods The Water Balance Questionnaire ( WBQ) was used to evaluate water balance, estimating water intake and loss in summer ( n = 480) and in winter ( n = 412) on a stratified sample of the general population in Athens, Greece. Results In winter, mean (SD) water balance was −63 (1478) mL/day−1, mean (SD)water intake was 2892 (987) mL/day−1 and mean (quartile range) water loss was 2637 (1810-3922) mL/day−1. In summer, mean (SD) water balance was −58 (2150) mL/day−1, mean (SD) water intake was 3875 (1373) mL/day−1 and mean (quartile range) water loss was 3635 (2365-5258) mL/day−1. Water balance did not differ between summer and winter ( P = 0.96); however, the data distribution was different; in summer, approximately 8% more participants were falling in the low and high water balance categories. Differences in water intake from different sources were identified ( P < 0.05). Conclusions Water balance in summer and winter was not different. However, water intake and loss were approximately 40% higher in summer than in winter. More people were falling in the low and high water balance categories in summer when comparing the distribution on water balance in winter. [ABSTRACT FROM AUTHOR]

Background: Evidence from animal and human studies suggests a protective effect of higher water intake on kidney function and cardiovascular disease (CVD). Here the associations between water intake, chronic kidney disease (CKD) and CVD were examined in the general population. Methods: We conducted a cross-sectional analysis of the 2005-2006 National Health and Nutrition Examination Survey. Non-pregnant adults with an estimated glomerular filtration rate (eGFR) ≥30 ml/min/1.73 m2 who were not taking diuretics were included. Total water intake from foods and beverages was categorized as low (<2.0 l/day), moderate (2.0-4.3 l/day) and high (>4.3 l/day). We examined associations between low total water intake and CKD (eGFR 30-60 ml/min/1.73 m2) and self-reported CVD. Results: Of 3,427 adults (mean age 46 (range 20-84); mean eGFR 95 ml/min/1.73 m2 (range 30-161)), 13% had CKD and 18% had CVD. CKD was higher among those with the lowest (<2.0 l/day) vs. highest total water intake (>4.3 l/day) (adjusted odds ratio (OR) 2.52; 95% confidence interval (CI) 0.91-6.96). When stratified by intake of (1) plain water and (2) other beverages, CKD was associated with low intake of plain water: adjusted OR 2.36 (95% CI 1.10-5.06), but not other beverages: adjusted OR 0.87 (95% CI 0.30-2.50). There was no association between low water intake and CVD (adjusted OR 0.76; 95% CI 0.37-1.59). Conclusions: Our results provide additional evidence suggesting a potentially protective effect of higher total water intake, particularly plain water, on the kidney. Copyright © 2013 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: Various recommendations exist for total water intake (TWI), yet it is seldom reported in dietary surveys. Few studies have examined how real-life consumption patterns, including beverage type, variety and timing relate to TWI and energy intake (EI). Methods: We analysed weighed dietary records from the National Diet and Nutrition Survey of 1724 British adults aged 19-64 years (2000/2001) to investigate beverage consumption patterns over 24 hrs and 7 days and associations with TWI and EI. TWI was calculated from the nutrient composition of each item of food and drink and compared with reference values. Results: Mean TWI was 2.53 L (SD 0.86) for men and 2.03 L (SD 0.71) for women, close to the European Food Safety Authority "adequate Intake" (AI) of 2.5 L and 2 L, respectively. However, for 33% of men and 23% of women TWI was below AI and TWI:EI ratio was <1 g/kcal. Beverages accounted for 75% of TWI. Beverage variety was correlated with TWI (r 0.34) and more weakly with EI (r 0.16). Beverage consumption peaked at 0800 hrs (mainly hot beverages/ milk) and 2100 hrs (mainly alcohol). Total beverage consumption was higher at weekends, especially among men. Overall, beverages supplied 16% of EI (men 17%, women 14%), alcoholic drinks contributed 9% (men) and 5% (women), milk 5-6%, caloric soft drinks 2%, and fruit juice 1%. In multi-variable regression (adjusted for sex, age, body weight, smoking, dieting, activity level and mis-reporting), replacing 100 g of caloric beverages (milk, fruit juice, caloric soft drinks and alcohol) with 100 g non-caloric drinks (diet soft drinks, hot beverages and water) was associated with a reduction in EI of 15 kcal, or 34 kcal if food energy were unchanged. Using within-person data (deviations from 7-day mean) each 100 g change in caloric beverages was associated with 29 kcal change in EI or 35 kcal if food energy were constant. By comparison the calculated energy content of caloric drinks consumed was 47 kcal/100 g. Conclusions: TWI and beverage consumption are closely related, and some individuals appeared to have low TWI. Energy from beverages may be partly compensated. A better understanding of interactions between drinking and eating habits and their impact on water and energy balance would give a firmer basis to dietary recommendations. [ABSTRACT FROM AUTHOR]

This study analysed the anatomical structure of the seed coats, identified the location of water uptake and evaluated the effects of alternating temperatures and heat treatment on the breaking of physical dormancy of two species of Fabaceae (Caesalpinioideae), Cassia leptophylla and Senna macranthera, from the Atlantic forest of Brazil. The seed coats of both species consisted of a cuticle (extra-hilar region) or remaining funicle region (hilar region), subcuticular layer, palisade layer with lignin, osteosclereids, sclerified parenchyma and white cells. The palisade layer was formed by elongated macrosclereids with a light line of callose. In thermally scarified seeds of C. leptophylla, water entered through the micropylar canal, and in S. macranthera the water entered through the lens. Alternating temperatures that ranged from 15 to 30°C did not break physical dormancy of either species; however, exposure to 50°C broke seed hardcoatedness, allowing the entrance of water in both species. [ABSTRACT FROM PUBLISHER]

Use of a sectional water-intake chamber permits a significant reduction in its length, and appreciably lowers construction outlays for the water-intake unit. [ABSTRACT FROM AUTHOR]

Lesions of the tuberomammillary complex, a neuroanatomical system closely related to the hypothalamic supraoptic and paraventricular nuclei, induce strong polydipsia in male rats. It was recently demonstrated that this increase in water intake is immediate, persistent, follows circadian rhythms and appears to be related to sodium regulation. The present study found that urine osmolality was significantly lower in tuberomammillary-lesioned animals vs. their respective controls at 8:00 h after surgery. Therefore, the aim of the present study was to examine the natriuretic effect of intraperitoneal oxytocin (OT) administration on medial ventral tuberomammillary nucleus (E3) polydipsia and polyuria of lesioned and control male rats. At 24:00 h post-lesion, OT blocked the hyperdipsic and polyuric responses of E3-lesioned animals but not those of non-lesioned controls, which did however significantly increase their water intake. Moreover, urinary osmolality and sodium excretion increased in E3 -lesioned animals that received OT but not in lesioned controls receiving physiological saline (992 ± 187.19 vs. 215.83 ± 23.39 mOsm/kg; 1.68 ± 0.13 vs. 0.47 ± 0.1 mEq/L). At 48:00 h post-lesion, OT administration also induced a higher intake of water and of simultaneously offered hypertonic NaCl (1.5%) in E3-lesioned animals. These results are interpreted in terms of the hypothalamic systems involved in sodium and water homeostasis. [ABSTRACT FROM AUTHOR]

This cross-sectional study measures the arsenic level in school children exposed to contaminated well water in a rural area in Mexico. Arsenic was measured in hair by hydride generation atomic absorption spectrophotometry. Overall, 110 children were included (average 10 years-old). Among 55 exposed children, mean arsenic level on hair was 1.3 mg/kg (range <0.006-5.9). All unexposed children had undetectable arsenic levels. The high level of arsenic in water was associated to the level in hair. However, exposed children drank less well water at school or at home than unexposed children, suggesting that the use of contaminated water to cook beans, broths or soups may be the source of arsenic exposure. [ABSTRACT FROM AUTHOR]

The effects of the 5-HT1A receptor agonist 8-OH-DPAT on food and water intake in male broiler chickens were investigated. The injection of 25 or 50 μg/kg of 8-OH-DPAT 15 min before refeeding in fasted animals produced a decrease in food intake. No effect was observed in drinking. The injection of 25 or 50 μg/kg of the 8-OH-DPAT 60 min after the start of refeeding did not produce any significant modification in food intake. No effect on drinking was recorded. The agonist 8-OH-DPAT injected 15 min before water presentation in water-deprived chickens, produced an increased drinking 60 min after the presentation of water. No effect on food intake was observed. The results show that the effect on food intake of the agonist 8-OH-DPAT in fasted–refed broiler chickens was similar to those observed in mammals and layer-strain chickens. However, the agonist did not alter significantly the food intake when the broilers were fed 60 min before the injection. These results are contrary to the observed effects in mammals and in layer-strain chickens. Probably, the selection for rapid growth rate in broilers causes modifications in the feeding control pattern. The comparison between broilers and layers strain may be a useful tool to elucidate the complex mechanisms involved in food and water intake regulation in chickens. [ABSTRACT FROM AUTHOR]

Background/Aim: Gastric bypass (GB) is usually designed to restrict food intake and to induce malabsorption. Gastric hormones have been thought to play a role in the regulation of food intake and body weight. The aim of the present study was to analyze feeding behavior after total gastrectomy (Gx) or GB in rats. Methods: Animals were subjected to Gx, GB, or sham operations. Eating and drinking behaviors after surgeries were assessed by a comprehensive laboratory animal monitoring system. Gastric hormones were measured by radioimmunoassay and energy density in feces by adiabatic bomb calorimeter. Results: Compared with sham operation, both Gx and GB reduced the body weight as measured during 3–8 weeks postoperatively, which was associated with increased energy expenditure per 100 g body weight. Daily accumulated food intake and meal size (during nighttime) were reduced following Gx, but not GB. The water intake (during daytime) was increased after Gx and GB. The energy density in feces was unchanged. Serum concentrations of ghrelin, obestatin, leptin, gastrin, and pancreastatin were greatly reduced after Gx. Conclusions: Control of food intake and meal size was independent of the food reservoir function of the stomach. Surgical depletion of gastric hormones is associated with reduced meal size, but increased water intake. Copyright © 2008 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

BACKGROUND: Findings on water and total fluid intake and bladder cancer are inconsistent; this may, in part, be due to different levels of carcinogens in drinking water. High levels of arsenic and chlorinated by-products in drinking water have been associated with elevated bladder cancer risk in most studies. A pooled analysis based on six case-control studies observed a positive association between tap water and bladder cancer but none for nontap fluid intake, suggesting that contaminants in tap water may be responsible for the excess risk. OBJECTIVES: We examined the association between total fluid and water consumption and bladder cancer risk, as well as the interaction between water intake and trihalomethane (THM) exposure, in a large case-control study in Spain. METHODS: A total of 397 bladder cancer cases and 664 matched controls were available for this analysis. Odds ratios (OR) were estimated using unconditional logistic regression, controlling for potential confounders. RESULTS: Total fluid intake was associated with a decrease in bladder cancer risk [OR = 0.62; 95% confidence interval (CI), 0.40-0.95 for highest vs. lowest quintile comparison]. A significant inverse association was observed for water intake (for > 1,399 vs. < 400 mL/day, OR = 0.47; 95% Cl, 0.33-0.66; p for trend < 0.0001), but not for other individual beverages. The inverse association between water intake and bladder cancer persisted within each level of THM exposure; we found no statistical interaction (p for interaction = 0.13). CONCLUSION: Findings from this study suggest that water intake is inversely associated with bladder cancer risk, regardless of THM exposure level. [ABSTRACT FROM AUTHOR]

The present study investigated the role of corticotropin-releasing hormone (CRH) in the lateral parabrachial nucleus (LPBN) in the behavioral control of body fluid homeostasis by determining the effect of bilateral injections of the CRH receptor antagonist, α-helical corticotropin-releasing factor (CRF)9-41, and the CRH receptor agonist, CRH, on sodium chloride (salt appetite) and water (thirst) intake. Groups of adult, male Sprague-Dawley rats had stainless-steel cannulas implanted bilaterally into the LPBN and were sodium depleted or water deprived. Bilateral injections of α-helical CRF9-41 into the LPBN significantly potentiated water and salt intake in the sodium-depleted rats when access to fluids was restored. Bilateral injections of α-helical CRF9-41 into the LPBN (1.0 µg) also increased sodium appetite in water-deprived rats. Conversely, in sodium-depleted animals, bilateral injections of CRH inhibited sodium chloride intake. These results suggest that there is an endogenous CRH inhibitory mechanism operating in the LPBN to modulate the intake of sodium (salt appetite). This mechanism may contribute to the behavioral control of restoration of body fluid homeostasis in sodium-deficient states. [ABSTRACT FROM AUTHOR]

The present study determined whether vasopressin (VP) secretion is inhibited by an oropharyngeal signal associated with swallowing fluids when dehydrated rats drink water, as it is when dehydrated dogs are used as experimental subjects (Thrasher, TN, Keil LC, and Ramsay DJ. Ant J Physiol Regul Integr Comp Physiol 253: R509–R515, 1987). VP levels in systemic plasma (pVP) fell rapidly when rats drank water after overnight water deprivation. Systemic plasma Na+ concentration (pNa) also fell, but that change likely contributed little to the early inhibition of VP secretion. In contrast, consumption of water by dehydrated rats with an open gastric fistula had no effect on pVP, nor did consumption of isotonic saline by dehydrated rats: in neither case was pNa affected by fluid consumption. These findings provide no evidence that the act of drinking inhibits VP secretion in dehydrated rats. Thus some postgastric effect of the ingested water seems to be responsible for the inhibitory signal. These results are consistent with previous suggestions that an early inhibitory stimulus for VP secretion in rats is provided by postgastric visceral osmo- or Na+ receptors that sense the composition of the ingested fluid. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine the function of the lateral parabrachial area (LPB) in relation to the intragastric administration of nutrients. The consumption of flavors associated with intragastric nutrient administration and the subsequent food and water intake were measured in rats with lesions in the LPB. The results showed that bilateral LPB lesions prevented development of aversions and induced flavor preference when there was a delay between the presentation of a flavor and the intragastric administration of nutrients. However, these lesions did not disrupt development of the aversive process when there was no delay between the presentations. Likewise, the LPB lesions increased subsequent food intake when there was a delay but not when there was no delay between the presentations. In contrast, the water intake was reduced in both situations. These results are interpreted in terms of a dual visceral system for processing the intragastric effects of foods. [ABSTRACT FROM AUTHOR]

Sensory awareness contributes to the enjoyment of eating and drinking. This study tested the hypothesis that changes in the intensity of oral sensations could be used to regulate the volume of intake. Forty women ( p p [ABSTRACT FROM AUTHOR]

The aim of the present work was to study the potential involvement of hypothalamic galanin system in the anorectic mechanism of fluoxetine in obese Zucker rats. Male obese Zucker (falfa) rats were administered fluoxetine (10 mg/kg; i.p.) daily for two weeks. The control group was given 0.9% NaCl solution. Significant decreases in food intake, final body weight and total body fat were observed after fluoxetine treatment. Although fluoxetine-treated rats showed a decrease in urine elimination, this effect was not enough to compensate decreased water intake, leading to dehydration, as showed by decreased body water content. Chronic fluoxetine administration increased the numbers of galanin positively immunostained neural cells in medial and lateral preoptic areas, lateral hypothalamic area and paraventricular nucleus (rostral and magnocellular regions), without changes in dorsomedial, ventromedial, supraoptic, suprachiasmatic and arcuate nuclei. Taken into account that galanin stimulates appetite, these results could represent rather a compensatory response against reduced food intake than a direct anorectic mechanism. Changes in the magnocellular region of the hypothalamic paraventricular nucleus suggest a role for galanin neural circuits at this level in fluoxetine-induced hydro-osmotic impairment. [ABSTRACT FROM AUTHOR]

The partitioning of nutrients and trace elements from feeds, drinking water and mineral supplements on growth, faeces and urine of growing cattle was studied with eight steers in a balanced Latin square design with two replicates, each comprising four treatments (diet compositions), four periods and four animals. The treatments were four rations with a silage proportion of 15, 30, 60 and 100% of the dry matter. Records were taken of the individual intake of silage, concentrates, mineral supplements and water, and excretions by collecting all urine and faeces. All feeds, urine, faeces and water were analysed for their content of Al, Ca, Cd, Cl, Co, Cu, Fe, K, Mg, Mn, Mo, N, Na, Ni, P, S, Se, and Zn. Elements that were mainly excreted in faeces (Ca, Cd, Cu, Fe, P, and Zn) tended to have a constant uptake in amount. As there is a fairly good correlation between DM consumption and faeces production, it is possible to estimate the amount of these elements excreted at farm level by analysing a faeces sample. Elements that are excreted in significant amounts in both faeces and urine (Cl, K, Mg, Mo, N, Na, S, and Se) tended to have a constant uptake over treatments as a fraction of the feed content. It is more difficult to estimate the amounts of these elements at farm level because it is more difficult to predict urine production than faeces production. [ABSTRACT FROM AUTHOR]

A monitoring program was undertaken to evaluate the adverse impacts of the El Arish power plant on the northeastern Sinai coast of Egypt. This program spanned 28 months and includes intensive hydrographic surveying, measurements of waves, longshore current, littoral drift, currents behind the breaker zone, offshore currents, sea-level variation and water quality. The shoreline dynamics of the region have been substantially disrupted due to the high-intensity longshore transport and the interruption of longshore transport by the shore-perpendicular intake breakwaters. Maximum erosion of 5.5 m/year has been documented east of the breakwater. This erosion has been continuing eastwards, threatening the resort centers on the downcoast beaches. On the other hand, accretion (11.7 m/year) is recorded along the western side of the breakwater, accumulating great volumes of sand which is transported to the east by littoral currents. Part of this sand enters the intake basin, causing sedimentation problems by the easterly and westerly littoral drifts and cross-shore currents. In other respect, an unprotected offshore channel dredged in front of the water discharger, east of the intake, acts as an effective trap for the predominantly easterly sand drift, subsequently interrupting sediments moving from the east, accelerating processes of erosion to the east. The cooling and wastewater discharging from the discharger to the sea are insignificantly warmer than the upcoast water and not contaminated with chemical wastes. The thermal and chemical plume has no significant effect on the quality of the coastal water in the region. [ABSTRACT FROM AUTHOR]

In our research, we analyzed the energy and water consumption in diamond mining and laboratory synthesis operations. We used publicly available reports issued by two market leaders, DeBeers and ALROSA, to estimate water and energy use per carat of a rough diamond. The efficiency of the two most popular synthesis technologies for artificial diamonds—High-Pressure-High-Temperature (HPHT) and Microwave-assisted Chemical Vapor Deposition (M-CVD)—was examined. We found that the modern HPHT presses, with open cooling circuits, consume about 36 kWh/ct when producing gem-quality and average-sized (near-) colorless diamonds. ALROSA and DeBeers use about 96 kWh/ct and 150 kWh/ct, respectively, including all energy required to mine. Energy consumption of M-CVD processes can be different and depends on technological conditions. Our M-CVD machine is the least energy-efficient, requiring about 215 kWh/ct in the single-crystal regime, using 2.45-GHz magnetron for the support synthesis. The M-CVD methods of individual synthetic companies IIa Technology and Ekati Mine are different from our results and equal 77 and 143 kWh/ct, respectively. Water consumption for the HPHT and M-CVD methods was insignificant: approximately zero and 0.002 m3/ct, respectively, and below 0.077 m3/ct for ALROSA-mined diamonds. This study touches upon the impact of the diamond production methods used on the carbon footprint. [ABSTRACT FROM AUTHOR]

Water is an essential nutrient for humans. A cross-sectional study was conducted among 159 young adults aged 18–23 years in Hebei, China. The total drinking fluids and water from food were obtained by 7-day 24 h fluid intake questionnaires and the duplicate portion method, respectively. Pearson's correlation coefficients were performed to determine the relationship between fluid intake and 24 h urinary biomarkers and plasma biomarkers. A multivariable partial least squares (PLS) model was used to identify the key predictors in modeling the total water intake (TWI) with 24 h urine biomarkers. Logistic regressions of the TWI against binary variables were performed, and the receiver operating characteristic curve (ROC) was analyzed to determine the cutoff value of the TWI for the optimal hydration status and dehydration without adjustments to favor either the sensitivity or specificity. In total, 156 participants (80 males and 76 females) completed the study. Strong relationships were found between the total drinking fluids, TWI, and 24 h urine biomarkers among young adults, especially for the 24 h urine volume (r = 0.784, p < 0.001; r = 0.747, p < 0.001) and osmolality (r = −0.589, p < 0.001; r = −0.477, p < 0.001), respectively. As for the FMU and plasma biomarkers, no strong relationships were found. The percentages of the variance in TWI explained by the PLS model with 13 urinary biomarkers were 66.9%. The optimal TWI values for assessing the optimal hydration and dehydration were 2892 mL and 2482 mL for young males, respectively, and 2139 mL and 1507 mL for young females, respectively. Strong relationships were found between the TWI, total drinking fluids, and 24 h urine biomarkers, but not with the FMU and plasma biomarkers, among young adults, including males and females. The 24 h urine biomarkers were more sensitive than the first morning urinary biomarkers in reflecting the fluid intake. The TWI was a reliable index for assessing the hydration statuses for young adults in free-living conditions. [ABSTRACT FROM AUTHOR]

Benzodiazepines, used in the clinic as anxiolytics, have in animal models been found specifically to attenuate behavioural suppression caused by response contigent aversive stimuli, non-reward or novelty. The effects have been interpreted in more general terms as 'behavioural disinhibition' or 'response perseveration' or in more specific terms as reduced 'reward delay' or as an attenuation of a 'behavioural inhibition system'. In a recent publication we have described an experimental test in which decision making in the rat can be studied. The model is derived from ethology, in particular from optimal foraging theory. In order to solve the task, the animal must choose correctly between two options. For each option the probability of its resulting in a reward (water) has to be estimated on the basis of available information and to be related to the cost of performing it. We found that diazepam, in a dose that did not significantly affect the ability to perform the options per se, caused a strong impairment when these options, on the basis of available information, had to be combined into functional sequences in a decision making procedure. The results obtained cannot be explained on the basis of disinhibition or response perseveration. The hypothesis is advanced that benzodiazepines alter decision making in a more nonspecific may, by, for example, affecting the evaluation of the learned significance of stimuli in the environment. [ABSTRACT FROM AUTHOR]

A series of seven experiments was designed to investigate the mechanism(s) responsible for sex differences in the effects of DFP, an irreversible anticholinesterase, on behavioural and physiological variables. It was found that female (Sprague-Dawley) rats were more resistant than males to the effects of DFP: decreases in body temperature and water intake were significantly less in the females. These effects were related to less inhibition of brain acetylcholinesterase (AChE) in female than in male animals. Of the five isoenzymes of AChE separated from homogenates of brain, one was relatively insensitive to the effects of DFP, but all were inhibited to a greater extent in male animals. In contrast to the effects of DFP, female rats were more sensitive to the hypothermic effects of pilocarpine, a directly acting muscarinic agonist, indicating that the resistance of females to the hypothermic effects of DFP could not be attributed to decreased sensitivity of muscarinic cholinergic receptors. Measurement of the degree of radioactivity in brain homogenates following the peripheral administration of {P}-DFP indicated that the uptake of DFP into the brain was less for female than for male rats. A final experiment confirmed that the females had higher baseline levels of serum cholinesterase activity. It was also found that DFP produced a greater degree of inhibition of this enzyme in females. These experiments suggest that female rats may be less sensitive to the effects of DFP because they have higher levels of serum cholinesterase, which can bind to DFP administered peripherally and reduce the amount available for penetration into the brain. The results also support the hypothesis that the behavioural and physiological effects of DFP are related to the anticholinesterase properties of the agent. [ABSTRACT FROM AUTHOR]

Water intake in water deprived rats was decreased by administration of a low dose of apomorphine (0.1 mg/kg s.c.). This dose is too low to induce hyperactivity and stereotypies. Four different dopamine (DA) D-2 antagonists were used to counteract this effect of apomorphine; haloperidol [an antipsychotic inducing extrapyramidal side-effects (EPS)], sulpiride (an antipsychotic inducing less EPS than haloperidol), metoclopramide (not used as an antipsychotic but inducing EPS) and domperidone (not passing through the blood brain barrier). Domperidone did not counteract the apomorphine effect, indicating a central mechanism of action for apomorphine. Metoclopramide did not counteract the apomorphine effect and, in higher doses, water intake was even further reduced. Sulpiride completely counteracted the apomorphine effect but, in higher doses, did not by itself reduce water intake. Haloperidol counteracted the apomorphine effect in a small dose-range and caused a further reduction in the water intake when given in high doses. The results can be explained by the existence of two subpopulations of D-2 receptors related to different functions. The model described may be used in screening experiments aimed at finding new antipsychotic drugs with a low incidence of EPS. [ABSTRACT FROM AUTHOR]

Properties of systemically applied angiotensin II in stimulating water intake of normally hydrated ducks were studied and the results compared with properties of angiotensin II-responsive neurons of the subfornical organ which are considered as targets for circulating angiotensin, II acting as a dipsogen. Following intravenous infusion of hypertonic saline (2000 mosmol·kg at 0.3 ml·min for 1 h), intravenous infusion of 0.3 ml·min isotonic saline with angiotensin II (200 ng·min), starting 1 h later, stimulated drinking in each case at an angiotensin II plasma level of about 1400 pg·ml. Without hypertonic priming, the same angiotensin II infusion did not stimulate drinking in each experiment; however, if effective, repeated infusions of ANGII induced stable dipsogenic responses. Angiotensin II infusions did not alter plasma levels of antidiuretic hormone. Sar-Ile-angiotensin II, a non-selective angiotensin II antagonist, acted weakly as a partial agonist when injused at a dose 200-fold higher than angiotensin II and effectively blocked the dipsogenic action of angiotensin II; this corresponds to the inhibition of angiotensin II-induced excitation by Sar-Ile-angiotensin II observed in duck subfornical organ neurons. DuP 753 (losartan), an angiotensin II antagonist specifically blocking AT receptors in mammals, had equivocal effects on angiotensin II-induced drinking in ducks at rates 50- and 200-fold higher than angiotensin II, which corresponds to the weak inhibitory action of this compound on angiotensin II-induced neuronal excitation in the duck SFO. Blood pressure was only marginally elevated by the applied angiotensin II dose and Sar-Ile-angiotensin II had no effect. [ABSTRACT FROM AUTHOR]