THE EFFECT OF ANALOGS OF ANGIOTENSIN-II ON DRINKING AND CARDIOVASCULAR-RESPONSES TO CENTRAL ANGIOTENSIN-II IN THE RAT

1. Intracerebroventricular (I.C.V.) infusion (60 ng h-1) of Isoleu5-angiotensin II (Isoleu5-AngII) and des-amine-angiotensin II (des-amine-AngII) in rats caused increased drinking behaviour and an increase in arterial blood pressure.2. Des-amine-AngII caused similar increases in heart rate and arterial blood pressure as AngII.3. Previous I.C.V. injection of the antagonists [Leu8]-AngII, des-amine-[Leu8]-AngII and octanoyl-[Leu8]-AngII prevented the increases in heart rate and blood pressure produced by I.C.V. infusion of AngII and caused partial reduction of the dipsogenic response.4. The three antagonists had no effect on the increase in arterial blood pressure and heart rate caused by des-amine-AngII. The drinking response was reduced by previous injection of [Leu8]-AngII and des-amine-[Leu8]-AngII but not by octanoyl-[Leu8]-AngII.5. In conclusion, Isoleu5-AngII and des-amine-AngII increase drinking behaviour, arterial blood pressure and heart rate when infused into the cerebral ventricle of rats. The study with the antagonists showed that des-amine-AngII probably binds more strongly to AngII-receptors.

LATERAL PARABRACHIAL SEROTONERGIC MECHANISMS - ANGIOTENSIN-INDUCED PRESSOR AND DRINKING RESPONSES

This study investigated the effects of bilateral injections of serotonergic receptor ligands into the lateral parabrachial nucleus (LPBN) on the presser and dipsogenic responses induced by intracerebroventricular (icv) injection of angiotensin II (ANG II). Rats with stainless steel cannulas implanted bilaterally into the LPBN and into the left lateral ventricle were used to study icy ANG II-induced water intake and presser responses. Pretreatment with the serotonergic 5-HT1/5-HT2 receptor antagonist methysergide (1-8 mu g/200 nl) bilaterally injected into the LPBN increased the water intake induced by icv ANG II (50 ng/mu l) administered via the lateral ventricle, but pretreatment with methysergide (4 mu g/200 nl) did not change the presser response produced by icy ANG II. After bilateral injection of either serotonin (5-HT, 5 mu g/200 nl) or the serotonergic 5-HT2a/5-HT2c receptor agonist (+/-)-2,5-dimetoxy-4-iodoamphetamine hydrochloride (DOI; 0.5-10 mu g/200 nl) into the LPBN, the water intake induced by ANG II was significantly reduced. These results are consistent with other observations indicating that the LPBN is associated with inhibitory mechanisms controlling water intake induced by ANG II treatment and suggest that serotonergic pathways may be involved in this effect.

Inhibitory effect of DUP-753 on the drinking responses of rats to central administration of noradrenaline and angiotensin II and to dehydration

We investigated the effect of losartan (DUP-753) on the dipsogenic responses produced by intracerebroventricular (icv) injection of noradrenaline (40 nmol/mu l) and angiotensin II (ANG II) (2 ng/mu l) in male Holtzman rats weighing 250-300 g. The effect of DUP-753 was also studied in animals submitted to water deprivation for 30 h. After control injections of isotonic saline (0.15 M NaCl, 1 mu l) into the lateral ventricle (LV) the water intake was 0.2 +/- 0.01 ml/h. DUP-753 (50 nmol/mu l) when injected alone into the LV of satiated animals had no significant effect on drinking (0.4 +/- 0.02 ml/h) (N = 8). DUP-753 (50 nmol/mu l) injected into the LV prior to noradrenaline reduced the water intake from 2.4 +/- 0.8 to 0.8 +/- 0.2 ml/h (N = 8). The water intake induced by injection of ANG II and water deprivation was also reduced from 9.2 +/- 1.4 and 12.7 +/- 1.4 ml/h to 0.8 +/- 0.2 and 1.7 +/- 0.3 ml/h (N = 6 and N = 8), respectively. These data indicate a correlation between noradrenergic pathways and angiotensinergic receptors and lead us to conclude that noradrenaline-induced water intake may be due to the release of ANG II by the brain. The finding that water intake was reduced by DUP-753 in water-deprived animals suggests that dehydration releases ANG II, and that AT(1) receptors of the brain play an important role in the regulation of water intake induced by deprivation.

Effect of intracerebroventricular injection of ramipril on the drinking response caused by injection of noradrenaline into the third ventricle

We studied the effect of ramipril injected into the third ventricle (3rdV) on the control of water intake induced by injection of noradrenaline into the 3rdV of adult male Holtzman rats (250-300 g) implanted with a chronic stainless steel cannula into the 3rdV. The injection volume was always 1 mu l and was injected over a period of 30-60 sec. Control animals were injected with 0.15 M NaCl. After the injection of isotonic saline (control, 0.15 M NaCl) into the 3rdV, water ingestion was 0.3 +/- 0.1 ml/h. Ramipril (1 mu g/mu l) injected into the 3rdV prior to isotonic saline produced no changes in water ingestion (0.4 +/- 0.2 ml/h). The injection of noradrenaline (40 nmol/mu l) after isotonic saline induced an increase in water intake (3.0 +/- 1.1 ml/h). The prior injection of ramipril decreased this ingestion to 1.8 +/- 0.3 ml/h. These data show that the inhibition of converting enzyme in the brain reduces the water intake induced by catecholaminergic stimulation. We conclude that the brain is able to transform the prodrug ramipril into the active drug ramiprilat.

Opiate activation suppresses the drinking, pressor and natriuretic responses induced by cholinergic stimulation of the medial septal area

The present study investigates the participation and interaction between cholinergic and opiate receptors of the medial septal area (MSA) in the regulation of Na+, K+ and water excretion, drinking and blood pressure regulation. Male Holtzman rats were implanted with stainless steel cannulae opening into the MSA. Na+, K+ and water excretion, water intake and blood pressure were measured after injection of carbachol (cholinergic agonist), FK-33824 (an opiate agonist) + carbachol or naloxone (an opiate antagonist) + carbachol into MSA. Carbachol (0.5 or 2.0 nmol) induced an increase in Na+ and K+ excretion, water intake and blood pressure and reduced the urinary volume. FK-33824 reduced the urinary volume and Na+ and K+ excretion. Previous injection of FK-33824 (100 ng) into the MSA blocked the increases in Na+ and K+ excretion, water intake and blood pressure induced by carbachol. Naloxone (10 μg) produced no changes in the effect of 2.0 nmol carbachol, but potentiated the natriuretic effect induced by 0.5 nmol dose of carbachol. These data show an inhibitory effect of opiate receptors on the changes in cardiovascular, fluid and electrolyte balance induced by cholinergic stimulation of the MSA in rats. © 1992.

Determination of pentachlorophenol in drinking water

In this study, an in situ derivatization and extraction method for the determination of pentachlorophenol (PCP) has been applied successfully in the analysis of water samples. The PCP derivative analysis was performed by gas-liquid chromatography with electron capture detection. The limit of detection of the method is 1 μg/L and recoveries averaged 78-108% for PCP acetate at levels of 2, 10 and 20 μg/L.

Morphology of testis and epididymis in an ethanol-drinking rat strain (UChA and UChB)

The objective of the present study was to analyze the prospective alterations of the testis and epididymis in a defined strain of alcoholic rats in order to contribute to our understanding of the effects of chronic alcoholism on reproduction. The testis and epididymis of the animals were submitted to morphological analysis by macroscopy, light microscopy and electron microscopy and to morphometric analysis. The UCh rats showed atrophy of the epithelium and reduction of testis and epididymis weight, liver hypertrophy and fat infiltration and alterations of the hypothalamus-pituitary axis. Ethanol induces changes in the weight and in the epithelium of the testis and epididymis and in the hypothalamus-pituitary axis of the UCh rats.

Morphology of the ventral lobe of the prostate and seminal vesicles in an ethanol-drinking strain of rats (UChA and UChB)

Chronic alcoholism alters reproduction and therefore may be responsible for alterations of prostate and seminal vesicles, which are the subject of this analysis in UCh ethanol-drinking rats. The prostate and seminal vesicles of 20 animals were submitted to macroscopic, light microscopy, electron microscopy and morphometric analysis. The UCh rats showed atrophy of the epithelium and reduction of the weight of the prostate and seminal vesicle, liver hypertrophy and fat infiltration and alterations of the hypothalamus-pituitary axis. Ethanol induces changes in the weight and in the epithelium of prostate and seminal vesicles and hypothalamus-pituitary axis of UCh rats.

Simultaneous determination of As, Cu, Mn, Sb, and Se in drinking water by GFAAS with transversely heated graphite atomizer and longitudinal zeeman-effect background correction

A method has been developed for the direct and simultaneous determination of As, Cu, Mn, Sb, and Se in drinking water by electrothermal atomic absorption spectrometry (ETAAS) using a transversely heated graphite tube atomizer (THGA) with longitudinal Zeeman-effect background correction. The thermal behavior of analytes during the pyrolysis and atomization stages was investigated in 0.028 mol L-1 HNO3, 0.14 mol L-1 HNO3 and 1 + 1 (v/v) diluted water using mixtures of Pd(NO3)2 + Mg(NO3)2 as the chemical modifier. With 5 μg Pd + 3 μg Mg as the modifier, the pyrolysis and atomization temperatures of the heating program of the atomizer were fixed at 1400°C and 2100°C, respectively, and 20 μL of the water sample (sample + 0.28 mol L-1 HNO3, 1 + 1, v/v), dispensed into the graphite tube, analytical curves were established ranging from 5.00 -50.0 μg L-1 for As, Sb, Se; 10.0 - 100 μg L-1 for Cu; and 20.0 - 200 μg L-1 for Mn. The characteristic masses were around 39 pg As, 17 pg Cu, 60 pg Mn, 43 pg Sb, and 45 pg Se, and the lifetime of the tube was around 500 firings. The limits of detection (LOD) based on integrated absorbance (0.7 μg L-1 As, 0.2 μg L-1 Cu, 0.6 μg L-1 Mn, 0.3 μg L-1 Sb, 0.9 μg L-1 Se) exceeded the requirements of the Brazilian Food Regulations (decree # 310-ANVS from the Health Department), which established the maximum permissible level for As, Cu, Mn, Sb, and Se at 50 μg L-1, 1000 μg L-1, 2000 μg L-1, 5 μg L-1, and 50 μg L-1, respectively. The relative standard deviations (n = 12) were typically < 5.3% for As, < 0.5% for Cu, < 2.1% for Mn, < 11.7% for Sb, and < 9.2% for Se. The recoveries of As, Cu, Mn, Sb, and Se added to the mineral water samples varied from 102-111%, 91-107%, 92-109%, 89-97%, and 101-109%, respectively. Accuracy for the determination of As, Cu, Mn, Sb, and Se was checked using standard reference materials NIST SRM 1640 - Trace Elements in Natural Water, NIST SRM 1643d - Trace Elements in Water, and 10 mineral water samples. A paired t-test showed that the results were in agreement with the certified values of the standard reference materials at the 95% confidence level.

Morphology of the vas deferens in an ethanol-drinking strain of rats (UChA and UChB)

Chronic alcoholism alters reproduction and therefore may be responsible for alterations of vas deferens, which are the subject of this analysis in UCh ethanol-drinking rats. The proximal and distal segments of the vas deferens of 20 animals were submitted to macroscopic, light microscopy, electron microscopy and morphometric analysis. The UCh rats showed atrophy of the epithelium of the vas deferens and alterations of the hypothalamus-pituitary axis. Ethanol induces changes in the epithelium of the vas deferens and hypothalamus-pituitary axis of UCh rats.

Effect of fortification of drinking water with iron plus ascorbic acid or with ascorbic acid alone on hemoglobin values and anthropometric indicators in preschool children in day-care centers in Southeast Brazil

Background. Iron-deficiency anemia currently is the most frequently occurring nutritional disorder worldwide. Previous Brazilian studies have demonstrated that drinking water fortified with iron and ascorbic acid is an adequate vehicle for improving the iron supply for children frequenting day-care centers. Objective. The objective of this study was to clarify the role of ascorbic acid as a vehicle for improving iron intake in children in day-care centers in Brazil. Methods. A six-month study was conducted on 150 children frequenting six day-care centers divided into two groups of three day-care centers by drawing lots: the iron-C group (3 day-care centers, n = 74), which used water fortified with 10 mg elemental iron and 100 mg ascorbic acid per liter, and the comparison group (3 day-care centers, n = 76), which used water containing only 100 mg ascorbic acid per liter. Anthropometric measurements and determinations of capillary hemoglobin were performed at the beginning of the study and after six months of intervention. The food offered at the day-care centers was also analyzed. Results. The fo od offered at the day-care center was found to be deficient in ascorbic acid, poor in heme iron, and adequate in non-heme iron. Supplementation with fortified drinking water resulted in a decrease in the prevalence of anemia and an increase in mean hemoglobin levels associated with height gain in both groups. Conclusions. Fortification of drinking water with iron has previously demonstrated effectiveness in increasing iron supplies. This simple strategy was confirmed in the present study. The present study also demonstrated that for populations receiving an abundant supply of non-heme iron, it is possible to control anemia in a simple, safe, and inexpensive manner by adding ascorbic acid to drinking water. © 2005, The United Nations University.

Faecal contamination (viral and bacteria) detection in groundwater used for drinking purposes in São Paulo, Brazil

This project has been developed to evaluate the possible relationship between the cesspit (pit latrine) in as far as it degrades the quality of underground water. Its importance is due to the fact that in the rural communities in the State of São Paulo (Brazil) this type of cesspit is very common as a means of sewage disposal and these communities use underground water for their supply of drinking water. Rural properties distributed over the rural area in the municipality of São José do Rio Preto were selected. A preliminary study was then set up to determine the social situation and health of the households as well as qualitative evaluations on the type of water supply and sewage disposal of these communities. Campaigns of water sampling then followed and laboratory analyses of water taken from wells were carried out. Parameters were set up to evaluate the potability according to Brazilian legislation (2004) paying attention to microbiologic (coliforms, Crytosporidium sp., and adenovirus). The analyses showed evidence of possible interaction between the wells and the sewage effluents and drainage in these communities. A PCR reaction to detect adenovirus showed a presence in 53.3% of the samples. The tests for the detection of Cryotosporidium sp all showed a negative result.

Cyanobacteria, microcystins and cylindrospermopsin in public drinking supply reservoirs of Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influence of microbiological quality of drinking water in the intestinal morphology of broilers

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)