Drinking after intragastric NaCl without increase in systemic plasma osmolality in rats

1995 ◽  
Vol 269 (5) ◽  
pp. R1085-R1092 ◽  
Author(s):  
F. S. Kraly ◽  
Y. M. Kim ◽  
L. M. Dunham ◽  
R. A. Tribuzio

Drinking after intragastric hypertonic solutions was examined to determine whether increased plasma osmolality always accompanied initiation of drinking. A 2-ml infusion through a gastric catheter was the beginning of tests in Sprague-Dawley male rats. Latency to drink was shorter and 1-h water intake was greater for increasing concentrations of NaCl (600, 1,200, and 1,800 mosmol/kg) compared with baseline (290 mosmol/kg). Although 600, 900, or 1,200 mosmol/kg NaCl elicited drinking, such infusions failed to change systemic plasma osmolality, and 900 mosmol/kg also failed to change plasma sodium, protein, renin activity, or packed cell volume at the initiation of drinking. Intragastric 900 mosmol/kg sodium bicarbonate, sodium isethionate, potassium chloride, lithium chloride, and mannitol differentially increased water intake. Total subdiaphragmatic vagotomy abolished drinking elicited by intragastric NaCl; selective gastric or hepatic vagotomy attenuated intake under some conditions. These results support the hypothesis of a vagally mediated, gastrointestinal and/or hepatic-portal, osmosensitive mechanism for initiation of drinking in advance of postprandial increases in systemic osmolality.

2008 ◽  
Vol 27 (3_suppl) ◽  
pp. 101-118 ◽  
Author(s):  
Eri Watanabe ◽  
Terutaka Kodama ◽  
Takeshi Masuyama ◽  
Shoji Tsubuku ◽  
Akira Otabe ◽  
...  

Dihydrocapsiate, (4-hydroxy-3-methoxybenzyl 8-methylnonanoate; CAS No. 205687-03-2) is a naturally occurring capsinoid compound found in nonpungent chili peppers. Although the safety of synthetically produced dihydrocapsiate has been previously evaluated, the purpose of this 13-week gavage toxicity study is to evaluate dihydrocapsiate produced with a slightly modified manufacturing process. Sprague-Dawley rats, 10 rats/sex/group, 6 weeks of age at study initiation, were administered the dihydrocapsiate daily by gavage at dose levels of 0 (vehicle), 100,300, or 1000 mg/kg/day. The rats were observed for antimortem and postmortem signs of toxicity, including changes in clinical signs, body weights, food consumption, water intake, ophthalmology, clinical pathology (clinical chemistry, hematology, urinalysis), tissue findings (macroscopic and microscopic examination), as well as organ weights. There were no changes observed in clinical signs, body weight, food consumption, water intake, ophthalmology, urinalysis, hematology, or blood chemistry that were attributable to the administration of dihydrocapsiate. The only change observed attributable to the dihydrocapsiate administration involved the liver and that change occurred only at the high dose (1000 mg/kg). Both sexes had an increase in organ weights, but this increase correlated with a change in histopathology (i.e., hepatocyte hypertrophy) only in the males. No dihydrocapsiate-related histopathological changes were observed in males at doses ≤300 mg/kg or in females at any of the doses tested (≤1000 mg/kg). It was concluded that the no observed adverse effect level (NOAEL) of dihydrocapsiate was 300 mg/kg/day for male rats and 1000 mg/kg/day for female rats in this 13 week gavage study.


1986 ◽  
Vol 251 (6) ◽  
pp. R1071-R1077 ◽  
Author(s):  
A. Saikaley ◽  
D. Bichet ◽  
J. Kucharczyk ◽  
L. N. Peterson

We investigated whether the increased intake of water during dietary electrolyte depletion is related to activation of the renin-angiotensin system. Young adult male rats were fed a low Na-, Cl-, K-free (low-salt) diet for 2 wk during which measurements were made of daily water intake and urine volume, plasma osmolality (Posm) and electrolytes, and plasma renin activity (PRA) and angiotensin I (ANG I) concentration. Water intake and urine output increased on day 3 of the low-salt diet, reached a maximum on day 4, and remained elevated, paralleling the time course of increases in PRA and ANG I plasma concentrations. Posm was normal after 2 days on the low-salt, although it was significantly lower by day 11. Renal concentrating ability was not different from controls after 6 days, but was significantly reduced after 11 days of treatment. Electrolytic lesions of the subfornical organ (SFO) abolished the low-salt diet-induced polydipsia, but had no effect on the diet-induced increases in PRA and plasma ANG I concentration. These data demonstrate that polydipsia induced by feeding a low-salt diet can develop in the presence of a normal or reduced Posm and precedes the development of a renal concentrating defect. The primary polydipsia is associated with elevated PRA and ANG I and appears to be mediated by angiotensin receptors in the SFO.


1990 ◽  
Vol 258 (4) ◽  
pp. F973-F979 ◽  
Author(s):  
N. Bouby ◽  
S. Bachmann ◽  
D. Bichet ◽  
L. Bankir

This study tests the possible influence of the urinary concentrating process and/or of vasopressin (AVP) on the progression of early chronic renal failure (CRF). Male Sprague-Dawley rats were submitted to 5/6 nephrectomy and were offered water ad libitum throughout the study. In addition, half of the rats (high water intake, HWI) received their food mixed with a water-rich agar gel. The other rats (normal water intake, NWI) ate the same amount of food plus agar in the usual dry powder form. This resulted in doubling the daily water ingestion in HWI. Renal function was studied for 10 wk and kidney morphology assessed thereafter. Increased water intake in HWI reduced solute-free water reabsorption and urine osmolality about threefold to 12 +/- 1 ml/day and 390 +/- 9 mosmol/kgH2O, respectively (week 5 as example). Hematocrit, plasma sodium, and plasma creatinine concentration were unchanged. The progressive increases in urinary protein excretion and in systolic blood pressure observed in this model of CRF were significantly slowed in HWI compared with NWI (at week 5, 8.6 +/- 1.8 vs. 23.1 +/- 6.2 mg protein/day and 142 +/- 8 vs. 167 +/- 10 mmHg, respectively). Remnant kidney weight per unit body weight was 21% lower in HWI than in NWI (P less than 0.02). Incidence of glomerulosclerosis was also reduced and was correlated with kidney weight (P less than 0.01). AVP plasma level (PAVP) and plasma renin activity (PRA) were measured in additional rats. PAVP was about twofold higher (P less than 0.05) and PRA twofold lower (P less than 0.001) in rats with 5/6 nephrectomy than in control rats with two kidneys.(ABSTRACT TRUNCATED AT 250 WORDS)


1998 ◽  
Vol 84 (5) ◽  
pp. 1653-1660 ◽  
Author(s):  
Martin G. Latour ◽  
François Désy ◽  
Claude Warren ◽  
Jean-Marc Lavoie

The present study was conducted to investigate the in vivo effects of an intrahepatic infusion of deionized water during exercise in rats. Adrenodemedullated male Sprague-Dawley rats were continuously infused for 30 min either at rest or during treadmill exercise (26 m/min, 0% grade). Rats were randomly assigned to one of three infusion conditions (52 μl/min) with either deionized water (PW) or saline (PS; NaCl; 0.9%) via the hepatic portal vein or deionized water through the jugular vein (JW). The exercise period caused a significant ( P < 0.05) decrease in liver glycogen and relative liver water content and peripheral and portal blood glucose and insulin while increasing peripheral and portal glucagon and K+ plasma concentrations. These responses, with the exception of K+, were not influenced by the different types of infusions. The increase in K+ during exercise was significantly ( P < 0.05) higher in JW rats than in the PW and PS groups. Both the infusion and exercise protocols did not significantly alter the liver weight-to-body weight ratio, plasma osmolality, free fatty acids, β-hydroxybutyrate, Na+, Cl−, vasopressin, and catecholamine concentrations. It is concluded that an hepatic portal infusion of deionized water does not specifically alter the metabolic and hormonal responses to exercise in rats.


1988 ◽  
Vol 254 (3) ◽  
pp. R478-R484 ◽  
Author(s):  
W. M. Barron ◽  
M. D. Lindheimer

Osmoregulation was studied throughout rodent pregnancy focusing on the importance of the fetoplacental unit and prolactin in the observed alterations. Plasma osmolality (Posmol) and plasma sodium (PNa), similar in 8-day gravid and virgin Sprague-Dawley rats, decreased significantly by gestational day 10, reaching a nadir 8-10 mosmol/kg and 3-5 meq/l, respectively, below virgin levels by day 14 (both P less than 0.001). Despite this, plasma arginine vasopressin (PAVP) was measurable and similar in all pregnant and virgin groups. Osmotic thresholds for arginine vasopressin (AVP) secretion, similar in 8-day gravid and virgin rats, decreased 7.7 and 10.7 mosmol/kg in 12- and 14-day pregnant rats, respectively (both P less than 0.001). In contrast, Posmol decreased less than 2 mosmol/kg in 12- to 14-day pseudopregnant animals. When pseudopregnancy was prolonged to 18 days by prior hysterectomy, Posmol was only 2.6 mosmol/kg below that of cycling, hysterectomized controls. In other studies 14 days of hyperprolactinemia evoked by estradiol or treatment with ovine or rat prolactin had minimal effect on Posmol. We conclude that parallel decrements in Posmol and osmotic thresholds for AVP release occur during early rodent pregnancy, alterations that cannot be explained by gestational increases in circulating prolactin. In addition, the failure of pseudopregnancy. to mimic the hypotonicity of gestation suggests an important role for the fetoplacental unit in the osmoregulatory changes of rat pregnancy.


Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1569
Author(s):  
Tomislav Šušnjar ◽  
Ivana Kuzmić Prusac ◽  
Ivan Švagelj ◽  
Anđela Jurišić ◽  
Tomislav Šušnjar ◽  
...  

Background: The aim of this study was to compare consequences in single and triple testicular biopsy by biopty gun in pubertal rats using histological and immunohistochemical analysis. Methods: Thirty-two Sprague-Dawley male rats were used as the experimental model. The rats were randomly divided into three study groups. The rats from the first group (n = 12) received a single-biopsy of upper pole of the left testis, while the rats from the second group (n = 10) received triple-biopsy of upper and lower poles and lateral surface of left testis. The third group (n = 10) was a control group. On the eightieth day after the biopsy in all rats bilateral orchiectomy and funiculectomy were performed to obtain testicular tissue and sperm for analysis. The consequences of the puncture were observed by pathohistology, immunohistochemistry and semen analysis. Results: The results of the study showed lower percentage of sperm count (14.5 mill/mL vs. 16 mill/mL, p = 0.130), sperm motility (24.6% vs. 32.7%, p > 0.05), abnormal sperm (30% vs. 27%, p > 0.05), atrophic tubules (21% vs. 6%, p < 0.001), volume (1.7 mL vs. 2.28 mL, p < 0.01) and apoptotic index (1.56 vs. 1.19, p = 0.650) in the testes with a triple-biopsy compared to the testes with a single-biopsy. Semen analysis showed a borderline significant difference between the group with triple-biopsy where sperm count was lower than it in the control group (14.5 mill/mL vs. 17.5 mill/mL, p = 0.05). A single-biopsy has little effect on the testis, especially on overall fertility. A triple-biopsy showed higher degree of the testicular damage but without a significant impact on overall fertility. Semen analysis showed that single- and triple-biopsies did not have a significant effect on sperm count, motility and morphology. Conclusion: Biopty gun procedure is a cheap, simple and reliable method for testicular biopsy in rats without a significant effect on sperm count, motility and morphology.


2021 ◽  
Vol 30 ◽  
pp. 096368972110354
Author(s):  
Eun-Jung Yoon ◽  
Hye Rim Seong ◽  
Jangbeen Kyung ◽  
Dajeong Kim ◽  
Sangryong Park ◽  
...  

Stamina-enhancing effects of human adipose derived stem cells (hADSCs) were investigated in young Sprague-Dawley rats. Ten-day-old male rats were transplanted intravenously (IV) or intracerebroventricularly (ICV) with hADSCs (1 × 106 cells/rat), and physical activity was measured by locomotor activity and rota-rod performance at post-natal day (PND) 14, 20, 30, and 40, as well as a forced swimming test at PND 41. hADSCs injection increased the moving time in locomotor activity, the latency in rota-rod performance, and the maximum swimming time. For the improvement of physical activity, ICV transplantation was superior to IV injection. In biochemical analyses, ICV transplantation of hADSCs markedly reduced serum creatine phosphokinase, lactate dehydrogenase, alanine transaminase, and muscular lipid peroxidation, the markers for muscular and hepatic injuries, despite the reduction in muscular glycogen and serum triglycerides as energy sources. Notably, hADSCs secreted brain-derived neurotrophic factor (BDNF) and nerve growth factor in vitro, and increased the level of BDNF in the brain and muscles in vivo. The results indicate that hADSCs enhance physical activity including stamina not only by attenuating tissue injury, but also by strengthening the muscles via production of BDNF.


2020 ◽  
Vol 19 (2) ◽  
pp. 296-303
Author(s):  
Eni Widayati ◽  
Taufiqurrachman Nasihun ◽  
Azizah Hikma Savitri ◽  
Nurina Tyagita

Objective: The effect of Pimpinela alpina Molk (PaM) on decrease in Bax and Caspase-3 protein expression in liver cells apoptosis have been proven. However, the difference result between 7 and 15 days treatment duration of PaM need to be confirmed. This study aimed to confirm that treatment of PaM during 15 days is more effective decreasing Bax and Caspase-3 protein expression in liver cells following UVB irradiation. Methods: In the post test only control group design, 35 Sprague Dawley male rats, 300 gram body weight were divided into two arms, consisting of three groups respectively. First arm comprise Neg-7, PaM7-100, and PaM7-150. Second arm comprise Neg-15, PaM15-100, and PaM15-150. Nor-G was added as normal control neither exposed to UVB nor PaM treatment. In negative group was only radiated to UVB and PaM groups were exposed to UVB and treatment with 100, and 150 mg PaM per oral for 7 and 15 days respectively. At day 8 (first arm) and 16 (second arm), liver organ was taken and Bax and Caspase-3 protein expression assessed by Immunohistochemical staining method. Result: Post Hoc LSD analysis indicated that Bax and Caspase-3 protein expression in PaM15-100 and PaM15-150 was significant lower compared to that of Nor-G, PaM7-100, and PaM7-150, p < 0.05. Conclusion: Ttreatment of PaM with doses 100 and 150 mg for 15 days was better in decreasing Bax and Caspase-3 protein expression of liver cells following UVB irradiation. Bangladesh Journal of Medical Science Vol.19(2) 2020 p.296-303


1994 ◽  
Vol 267 (2) ◽  
pp. H751-H756 ◽  
Author(s):  
A. W. Cowley ◽  
E. Szczepanska-Sadowska ◽  
K. Stepniakowski ◽  
D. Mattson

Despite the well-recognized vasoconstrictor and fluid-retaining actions of vasopressin, prolonged administration of arginine vasopressin (AVP) to normal animals or humans fails to produce sustained hypertension. The present study was performed to elucidate the role of the V1 receptor in determining the ability of AVP to produce sustained hypertension. Conscious Sprague-Dawley rats with implanted catheters were infused with the selective V1 agonist, [Phe2,Ile3,Orn8]vasopressin (2 ng.kg-1.min-1), for 14 days in amounts that were acutely nonpressor. Blood pressure (MAP), heart rate (HR), body weight, and water intake (WI) were determined daily. Plasma AVP, plasma catecholamines norepinephrine and epinephrine, plasma osmolality, and electrolyte concentration were determined before and on days 1 and 7 of infusion. MAP increased significantly by 10.4 +/- 4.5 mmHg on day 1 and rose to 22 +/- 5 mmHg above control by day 14 (transient decrease on days 6-9) and then fell to control levels after the infusion was stopped. HR did not change significantly. Plasma AVP immunoreactivity increased from 2.5 +/- 0.3 to 10.9 +/- 2.1 pg/ml, whereas norepinephrine tended to fall only on day 1, with epinephrine only slightly elevated on day 7. No evidence of fluid retention was found, and rats lost sodium only on the first day of V1 agonist infusion. Body weight increased throughout the study but was unrelated to the changes of MAP. We conclude that chronic stimulation of V1 receptors results in sustained hypertension in rats.


1979 ◽  
Vol 16 (5) ◽  
pp. 574-582 ◽  
Author(s):  
J. J. Berman ◽  
J. M. Rice

A single intraperitoneal dose of methyl(acetoxymethyl)nitrosamine (13 mg/kg body weight) given to 78 5-week-old male rats induced 25 mesotheliomas; two mesotheliomas were found in 67 control rats. All mesotheliomas arose from the peritesticular mesothelium and had a typical microscopic appearance of branching papillary fronds with a collagenous core covered by one or many layers of plump tumor cells. Cytoplasm of tumor cells contained material that reacted positively to a colloidal iron stain and was labile to hyaluronidase. In addition to frank mesotheliomas, 16 lesions, which we called atypical mesothelial proliferations. were found. These consisted of a single focus of plump mesothelial cells overlying an area of thick stroma. Often these foci included short, non-branched papillary projections above the surface of adjacent normal mesothelium. Twelve of the 16 lesions occurred in methyl(acetoxymethyl)nitrosamine-treated rats.


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