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Water Deprivation (water + deprivation)
Selected AbstractsTime Of Day And Access To Food Alter Water Intake In Rats After Water DeprivationCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 9 2001Kooi K Ang SUMMARY 1. Drinking behaviour after water deprivation is one of the standard tests used to study thirst in humans and animals. Diurnal cycle and food availability are known to influence water intake, but have not been considered in previous studies of thirst after water deprivation. In the present study, we examined the effects of diurnal variation and food availability on water intake after 24 h water deprivation in rats. 2. All rats cycled through four treatments in varying order. These treatments were: (i) 24 h water deprivation with free access to food from 1900 h one day to 1900 h the next day, followed by free access to both food and water (Night-with-Food); (ii) 24 h water deprivation with free access to food from from 1900 h one day to 1900 h the next day, followed by free access to water but not food (Night-without-Food); (iii) 24 h water deprivation with free access to food from 0700 h one day to 0700 h the next day, followed by free access to both food and water (Day-with-Food); or (iv) 24 h water deprivation with free access to food from 0700 h one day to 0700 h the next day, followed by free access to water but not food (Day- without-Food). The amount of water consumed during the first 6 h, post-24 h water deprivation, was examined under each condition. 3. There was a significant diurnal effect (P < 0.001) and a significant food availability effect (P = 0.007) on the water consumed in the 6 h period after water deprivation. Most water was consumed by the Night-with-Food group and the least amount of water was consumed by the Day-without-Food group. These effects persisted after correction for water intake during 6 h periods from 0700 and 1900 h with and without food but without previous water deprivation. The diurnal and food availability effects on water consumption were independent (P = 0.5). 4. The coefficient of variability for each group suggests that the most sensitive measurements of water intake are obtained during the day in the absence of food. 5. We conclude that both the time of day and access to food independently alter water intake in rats subjected to a previous 24 h water deprivation. Our study also supports the validity of performing water intake measurements in thirst studies in rats during the day. [source] Sertraline, a selective serotonin reuptake inhibitor, affects thirst, salt appetite and plasma levels of oxytocin and vasopressin in ratsEXPERIMENTAL PHYSIOLOGY, Issue 5 2007Ana Paula De Magalhães-Nunes We investigated the effects of chronic administration of sertraline (SERT; ,20 mg kg,1 day,1 in drinking water), a selective serotonin reuptake inhibitor, on water and sodium intake and on plasma levels of oxytocin (OT) and vasopressin (AVP) in basal and stimulated conditions. Basal water intake was reduced in SERT-treated rats. After 24 h of water deprivation, rats treated with SERT for 21 days ingested less water than the control rats (9.7 ± 0.5 versus 20.0 ± 0.9 ml, respectively, at 300 min after water presentation, P < 0.0001). Subcutaneous injection of 2 m NaCl or isoproterenol evoked a lower dipsogenic response in rats treated with SERT for 21 days. Fluid and food deprivation also induced a weaker dipsogenic response in SERT-treated rats (1.6 ± 0.5 versus 10.2 ± 1.2 ml, at 300 min, P < 0.0001) but had no effect on saline intake. Sodium depletion induced a higher natriorexigenic response in the SERT group (5.6 ± 1.3 versus 1.2 ± 0.3 ml, at 300 min, P < 0.0002). Higher urinary density and lower plasma sodium levels were observed after SERT treatment. Sertraline also increased plasma levels of vasopressin and oxytocin (AVP, 2.65 ± 0.36 versus 1.31 ± 0.16 pg ml,1, P < 0.005; OT, 17.16 ± 1.06 versus 11.3 ± 1.03 pg ml,1, P < 0.0009, at the third week post-treatment). These data constitute the first evidence that chronic SERT treatment affects water and sodium intake in rats. These effects seem to be related to the hyponatraemia caused by the higher plasma levels of AVP and OT. [source] Lesions of the Diagonal Band of Broca Enhance Drinking in the RatJOURNAL OF NEUROENDOCRINOLOGY, Issue 10 2003M. J. Sullivan Abstract This study examined the role of the diagonal band of Broca (DBB) in drinking behaviour and vasopressin release. Adult male rats were anaesthetized (pentobarbital 50 mg/kg) and received DBB injections of either ibotenic acid (0.5 µl of 5 µg/µl) or vehicle (0.5 µl of phosphate-buffered saline). Although baseline drinking and urine output were not affected, drinking to 30% polyethylene glycol (MW 8000; 1 ml/100 g s.c.) and angiotensin II (0, 1.5 and 3.0 mg/kg s.c.) were significantly increased in ibotenic acid in phosphate-buffered saline (DBBX) rats. Drinking to hypertonic saline (0.9, 4 and 6%; 1 ml/100 g), and water deprivation were not significantly affected. DBBX rats had significantly lower basal heart rates than controls but the cardiovascular responses to infusions of angiotensin II (100 ng/kg/min i.v. for 45 min) were not affected. DBBX rats had significantly higher basal vasopressin, but angiotensin-stimulated vasopressin release was not significantly different. Although the DBB is not involved in basal water intake, it is involved in dipsogenic responses to hypovolemic stimuli and possibly basal autonomic function and basal vasopressin release. [source] Applied environmental stresses to enhance the levels of polyphenolics in leaves of hawthorn plantsPHYSIOLOGIA PLANTARUM, Issue 2 2004Ara Kirakosyan In this investigation, two species of Crataegus (hawthorn) were chosen because their polyphenolic constituents have recently received greater attention for the treatment of patients with severe heart disease. One-year-old plants of hawthorn (Crataegus laevigata and C. monogyna) were subjected to water-deficit (continuous water deprivation), cold (4°C), flooding (immersion of roots of plants in water) or herbivory (leaf removal) stress treatments (each of 10 days duration) in order to assess their effects on levels of polyphenolics, namely (-)-epicatechin, catechin, chlorogenic acid, vitexin, vitexin-2,,- O -rhamnoside, acetylvitexin-2,,- O -rhamnoside, hyperoside, quercetin, and rutin in the leaves. The working hypothesis followed is that one or more of these stress treatment will elicit increases in the levels of these polyphenolics. Cold stress causes increases in levels of vitexin-2,,- O -rhamnoside, acetylvitexin-2,,- O -rhamnoside, hyperoside, and quercetin in both Crataegus species. Water-deficit stress increased the productivity of chlorogenic acid, catechin, and (-)-epicatechin in both hawthorn species. Flooding and herbivory caused no net increases, and in some cases, decreases in levels of polyphenolics. These studies indicate that either water-deficit stress or cold stress treatments, or a combination of the two, can be used to enhance the levels of desired polyphenolics in the leaves of these two hawthorn species in a photobioreactor system. These results may have significance for hawthorn in adapting to water-deficit or cold stress and are important considerations for the use of hawthorn in the treatment of heart disease in humans. [source] Effects of water deprivation on the pharmacokinetics of metformin in ratsBIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 7 2007Young H. Choi Abstract It was reported that metformin was mainly metabolized via hepatic CYP2C11, 2D1 and 3A1/2 in rats, and in a rat model of dehydration, the expressions of hepatic CYP2C11 and 3A1/2 were not changed. Hence, it could be expected that the Clnr of metformin is comparable between two groups of rats if the contribution of CYP2D1 in the rat model of dehydration is not considerable. It was also reported that the timed-interval renal clearance of metformin was dependent on the urine flow rate in rats. In the rat model of dehydration, the 24h urine output was significantly smaller than in the controls. Hence, the urinary excretion of metformin was expected to be smaller than the controls. The above expectations were proven as follows. After intravenous administration of metformin (100mg/kg) to the rat model of dehydration, the Clnr were comparable between the two groups of rats. After both intravenous and oral administration of metformin (both 100mg/kg) to the rat model of dehydration, the 24h urinary excretion of the drug was significantly smaller than in the controls. After oral administration of metformin to the rat model of dehydration, the AUC was significantly greater (99.2% increase) than the controls. Copyright © 2007 John Wiley & Sons, Ltd. [source] Pharmacokinetics of omeprazole in rats with water deprivation for 72 hoursBIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 8 2006Dae Y. Lee Abstract Dehydration can occur by excessive sweating, polyuria, severe diarrhea and hyperthermia. Previous studies reported that the expressions of CYP1A1/2 and 3A1(23)/2 were not changed in male Sprague,Dawley rats with 72 h water deprivation (dehydrated rats), and that the metabolism of omeprazole is mainly catalysed via CYP1A1/2, 2D1 and 3A23/2 in rats. Hence, it could be expected that the hepatic metabolism of omeprazole would not be changed considerably in dehydrated rats, if the contribution of CYP2D1 to the metabolism of omeprazole in dehydrated rats is not considerable. Therefore, the pharmacokinetics of omeprazole were compared after intravenous (20 mg/kg) and oral (40 mg/kg) administration in control rats and in dehydrated rats. After intravenous administration, the time-averaged nonrenal clearance (Clnr) values of omeprazole were comparable between the two groups of rats. This could be supported by comparable in vitro intrinsic clearance (Clint) values for the disappearance of omeprazole in rat hepatic microsomes and the comparable free (unbound to plasma proteins) fractions of omeprazole in plasma in the two groups of rats. After oral administration, the AUC values of omeprazole were also comparable in the two groups of rats. The above data suggest that the dehydration state did not affect considerably the pharmacokinetics of omeprazole in rats. Copyright © 2006 John Wiley & Sons, Ltd. [source] INTRAPERITONEAL GLYCEROL INDUCES OXIDATIVE STRESS IN RAT KIDNEYCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 8 2008Elenara Rieger SUMMARY 1Glycerol has been used for the treatment of intracranial hypertension, cerebral oedema and glaucoma. Experimentally, intramuscular administration of hypertonic glycerol solution is used to produce acute renal failure. In this model, glycerol causes rhabdomyolysis and myoglobinuria, resulting in the development of renal injury. The pathogenesis is thought to involve vascular congestion, the formation of casts and oxidative stress. However, the effect of glycerol itself independent of rhabdomyolysis has not been investigated. Therefore, the aim of the present study was to investigate the effects of i.p. glycerol on some biochemical and oxidative stress parameters in the kidney of young rats. 2Rats received 10 mL/kg, i.p., hypertonic glycerol solution (50% v/v) or saline (NaCl 0.85 g%) followed by 24 h water deprivation. Twenty-four hours after the administration of glycerol, rats were killed. Creatinine levels and the activity of creatine kinase (CK) and lactate dehydrogenase (LDH) were determined in the plasma. In addition, CK, pyruvate kinase and LDH activity and oxidative stress parameters (free radical formation, lipid peroxidation and protein carbonylation) were measured in renal tissue. 3Glycerol did not alter plasma CK activity and increased plasma creatinine levels, suggesting renal insufficiency and the absence of rhabdomyolysis. Renal CK and pyruvate kinase activity was decreased, suggesting diminution of energy homeostasis in the kidney. Plasma and renal LDH activity was decreased, whereas the formation of free radicals, lipid peroxidation and protein carbonylation were increased, suggesting oxidative stress. 4These results are similar to those described after the intramuscular administration of glycerol. Therefore, it is possible that glycerol may provoke renal lesions by mechanisms other than those induced by rhabdomyolysis. [source] Time Of Day And Access To Food Alter Water Intake In Rats After Water DeprivationCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 9 2001Kooi K Ang SUMMARY 1. Drinking behaviour after water deprivation is one of the standard tests used to study thirst in humans and animals. Diurnal cycle and food availability are known to influence water intake, but have not been considered in previous studies of thirst after water deprivation. In the present study, we examined the effects of diurnal variation and food availability on water intake after 24 h water deprivation in rats. 2. All rats cycled through four treatments in varying order. These treatments were: (i) 24 h water deprivation with free access to food from 1900 h one day to 1900 h the next day, followed by free access to both food and water (Night-with-Food); (ii) 24 h water deprivation with free access to food from from 1900 h one day to 1900 h the next day, followed by free access to water but not food (Night-without-Food); (iii) 24 h water deprivation with free access to food from 0700 h one day to 0700 h the next day, followed by free access to both food and water (Day-with-Food); or (iv) 24 h water deprivation with free access to food from 0700 h one day to 0700 h the next day, followed by free access to water but not food (Day- without-Food). The amount of water consumed during the first 6 h, post-24 h water deprivation, was examined under each condition. 3. There was a significant diurnal effect (P < 0.001) and a significant food availability effect (P = 0.007) on the water consumed in the 6 h period after water deprivation. Most water was consumed by the Night-with-Food group and the least amount of water was consumed by the Day-without-Food group. These effects persisted after correction for water intake during 6 h periods from 0700 and 1900 h with and without food but without previous water deprivation. The diurnal and food availability effects on water consumption were independent (P = 0.5). 4. The coefficient of variability for each group suggests that the most sensitive measurements of water intake are obtained during the day in the absence of food. 5. We conclude that both the time of day and access to food independently alter water intake in rats subjected to a previous 24 h water deprivation. Our study also supports the validity of performing water intake measurements in thirst studies in rats during the day. [source] | |||||||||||||