Repletion of acute sodium deficit in rats drinking either low or high concentrations of sodium chloride solution

1992 ◽  
Vol 262 (3) ◽  
pp. R419-R425 ◽  
Author(s):  
N. E. Rowland ◽  
M. J. Fregly
Keyword(s):  
Sodium Depletion ◽  
Sprague Dawley ◽  
Plasma Parameters ◽  
Sodium Appetite ◽  
Sprague Dawley Rats ◽  
Body Sodium ◽  
Excessive Intake ◽  
High Concentrations ◽  
The Relationship ◽  
Cumulative Intake

These studies investigate the relationship between expression of sodium appetite and restoration of physiological normalcy after acute sodium depletion in Sprague-Dawley rats. After depletion (treatment with diuretic and 24 h without NaCl), separate groups of rats were allowed to drink either a low (0.03 M) or a high (0.3 M) concentration of NaCl. Intake and urinary output of sodium and selected plasma measures were made at various times up to 48 h. Depleted rats with access to 0.3 M NaCl consumed more Na+ than their deficit in the first hour and were volume expanded as a result of this excessive intake, but they continued to consume NaCl for 6-12 h. Depleted rats given 0.03 M NaCl drank a comparable volume to the 0.3 M group in the first hour and thus only approximately 10% of the solute. The intake of 0.03 M NaCl slowed after 6-12 h, at which time the cumulative intake matched the deficit and the plasma parameters had returned to nondepleted levels. Under these conditions of slow intake, it appears that sodium appetite is more closely matched to need than is the case when highly concentrated sources of sodium are available. Satiation of sodium appetite seems to require the passage of time as well as repletion of body sodium.

scholarly journals Assessment of carbon dioxide, carbon dioxide/oxygen, isoflurane and pentobarbital killing methods in rats

2016 ◽  
Author(s):  
Jessica M Chisholm ◽  
Daniel SJ Pang
Keyword(s):  
Carbon Dioxide ◽  
Heart Rate ◽  
Loss Of Consciousness ◽  
Sprague Dawley ◽  
Loss Of Righting Reflex ◽  
Sprague Dawley Rats ◽  
General Order ◽  
Righting Reflex ◽  
High Concentrations ◽  
The Relationship

AbstractBackground:Exposure to carbon dioxide (CO2) gas as a killing method is aversive and exposure to high concentrations likely to be painful. Bradycardia during exposure to CO2 is associated with nociception and pain. However, it is unclear if bradycardia occurs before loss of consciousness as this is variably defined in the literature. The objectives of this study were to explore the relationship between recumbency, loss of righting reflex (LORR) and a quiescent electromyograph as measures of loss of consciousness, and identify the onset of bradycardia in relation to these measures.Methods:Thirty-two adult, female Sprague-Dawley rats were instrumented with a telemetry device and randomly assigned to one of four killing methods (100% CO2, CO2 (70%)/O2 (30%), isoflurane (5%) and intraperitoneal pentobarbital (200 mg/kg). Time to achieve recumbency, LORR, quiescent electromyograph, isoelectric electrocorticograph, heart rate and apnea were recorded.Results:The general order of progression was recumbency, LORR, quiescent electromyograph, isoelectric electrocorticograph and apnea. Recumbency preceded LORR in the majority of animals (CO2; 7/8, CO2/O2; 8/8, isoflurane; 5/8, pentobarbital; 4/8). Bradycardia occurred before recumbency in the CO2 (p = 0.0002) and CO2/O2 (p = 0.005) groups, with a 50% reduction in heart rate compared to baseline. The slowest (time to apnea) and least consistent killing methods were CO2/O2 (1180 ± 658.1s) and pentobarbital (875 [239 to 4680]s).Conclusion:Bradycardia, and consequently nociception and pain, occurs before loss of consciousness during CO2 exposure. Pentobarbital displayed an unexpected lack of consistency, questioning its classification as an acceptable euthanasia method in rats.

scholarly journals Age-related decline in the taurine content of the skin in rodents

Amino Acids ◽  
2021 ◽  
Author(s):  
Tomohisa Yoshimura ◽  
Yuki Inokuchi ◽  
Chikako Mutou ◽  
Takanobu Sakurai ◽  
Tohru Nagahama ◽  
...  
Keyword(s):  
High Performance ◽  
Age Groups ◽  
Immunohistochemical Analysis ◽  
Sprague Dawley ◽  
Taurine Supplementation ◽  
Hairless Mice ◽  
Age Related ◽  
Sprague Dawley Rats ◽  
High Concentrations ◽  
Effects Of Aging

AbstractTaurine, a sulfur-containing amino acid, occurs at high concentrations in the skin, and plays a role in maintaining the homeostasis of the skin. We investigated the effects of aging on the content and localization of taurine in the skin of mice and rats. Taurine was extracted from the skin samples of hairless mice and Sprague Dawley rats, and the taurine content of the skin was determined by high-performance liquid chromatography (HPLC). The results of the investigation revealed that the taurine content in both the dermis and epidermis of hairless mice declined significantly with age. Similar age-related decline in the skin taurine content was also observed in rats. In contrast, the taurine content in the sole remained unchanged with age. An immunohistochemical analysis also revealed a decreased skin taurine content in aged animals compared with younger animals, although no significant differences in the localization of taurine were observed between the two age groups. Supplementation of the drinking water of aged mice with 3% (w/v) taurine for 4 weeks increased the taurine content of the epidermis, but not the dermis. The present study showed for the first time that the taurine content of the skin decreased with age in mice and rats, which may be related to the impairment of the skin homeostasis observed with aging. The decreased taurine content of the epidermis in aged animals was able to be rescued by taurine supplementation.

Time course of airway hyperresponsiveness and remodeling induced by hyperoxia in rats

1995 ◽  
Vol 269 (2) ◽  
pp. L227-L233 ◽  
Author(s):  
J. L. Szarek ◽  
H. L. Ramsay ◽  
A. Andringa ◽  
M. L. Miller
Keyword(s):  
Smooth Muscle ◽  
Airway Hyperresponsiveness ◽  
Time Course ◽  
Electrical Field Stimulation ◽  
Maximal Response ◽  
Sprague Dawley ◽  
Electrical Field ◽  
Muscle Area ◽  
Sprague Dawley Rats ◽  
The Relationship

The purpose of this study was to answer two questions concerning hyperoxia-induced airway hyperresponsiveness: 1) What is the time course of the development of airway hyperresponsiveness? 2) What is the relationship between the increase in responsiveness and smooth muscle area? Segments of intrapulmonary bronchi were isolated from male Sprague-Dawley rats that had been exposed to 80-85% O2 for a period of 1, 3, 5, or 7 days and from aged-matched control animals that breathed room air. Hyperoxia increased the sensitivity (log concentration or frequency that elicited a half-maximal response) and reactivity (maximum tension developed) of the airways to electrical field stimulation (EFS) after 3, 5, and 7 days; sensitivity to acetylcholine was not affected, but reactivity was increased after 7 days. Hyperoxia increased smooth muscle area beginning 5 days after commencing the exposure. After normalizing tension responses to smooth muscle area, reactivity of the airways to the stimuli was not different between the two groups, but sensitivity to EFS was still increased. The increase in reactivity observed after 5 and 7 days of exposure can be explained by an increase in smooth muscle area that occurred at these time points. The fact that the sensitivity of the airways to EFS remained increased after normalization, together with the fact that the increase in airway responsiveness after 3 days of exposure occurred at a time when smooth muscle area was not different from control, suggests that mechanisms other than increased smooth muscle area contribute to the development of hyperoxia-induced airway hyperresponsiveness.

Defect in the Renal Tubular Reabsorption of Water Associated With Potassium Depletion in Rats

1957 ◽  
Vol 189 (3) ◽  
pp. 557-563 ◽  
Author(s):  
Walter Hollander ◽  
Robert W. Winters ◽  
T. Franklin Williams ◽  
John Bradley ◽  
Jean Oliver ◽  
...  
Keyword(s):  
Urinary Concentration ◽  
Potassium Depletion ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Renal Tubular Reabsorption ◽  
Renal Concentrating Mechanism ◽  
Renal Tubular ◽  
Relationship Of ◽  
The Relationship ◽  
K Depletion

The effect of graded degrees of K depletion on the ability to produce a concentrated urine was studied in Sprague-Dawley rats. With increasing degrees of K depletion, as measured by the concentration of K in fat-free skeletal muscle, there was a progrossive decrease in the maximum urinary concentration. This defect of the renal concentrating mechanism appeared to be better correlated with the degree than with the duration of potassium depletion and could be demonstrated either by the use of exogenous vasopressin or by water deprivation. The potassium-deficient rats in at least one experiment developed a significant polydipsia. The data do not allow any conclusions with respect to the relationship of the polydipsia to the renal concentrating defect except that the latter at least was not severe at the onset of the increased water intake.

Decreased vascular sensitivity to norepinephrine following exercise training

1981 ◽  
Vol 51 (2) ◽  
pp. 282-287 ◽  
Author(s):  
D. L. Wiegman ◽  
P. D. Harris ◽  
I. G. Joshua ◽  
F. N. Miller
Keyword(s):  
Blood Pressure ◽  
Exercise Training ◽  
Sprague Dawley ◽  
Maximal Increase ◽  
Arterial Blood ◽  
Sprague Dawley Rats ◽  
Vascular Sensitivity ◽  
Series Of Experiments ◽  
High Concentrations ◽  
Alpha Chloralose

Twenty Sprague-Dawley rats (230 +/- 9 g; mean +/- SE) were exercised daily for 6 wk by swimming 1 h/day with weights (5% of body wt) attached to their tails. Nineteen additional rats (237 +/- 8 g) remained sedentary in their cages. All animals were anesthetized with urethan (800 mg/kg) and alpha-chloralose (60 mg/kg). In the first series of experiments, increasing doses of norepinephrine were injected into the jugular vein and the responses in mean arterial blood pressure was recorded from a cannulated femoral artery. Exercise training had no effect on the maximal increase in blood pressure, but significantly decreased blood pressure sensitivity to norepinephrine, expressed as a pD2 value (=-log ED 50), from 5.64 +/- 0.07 to 5.20 +/- 0.06. In the second series, the cremaster muscle with intact circulation and innervation was suspended in a tissue bath and norepinephrine in increasing concentrations was added to the cremaster bath. The responses of the main arteriole (approximately 110 micron) and venule (approximately 170 micron) were recorded by television microscopy. Exercise training had no effect on vessel diameters of resting muscle or on the maximal vessel constrictions obtained in response to high concentrations of norepinephrine. Arteriole sensitivity to norepinephrine was significantly decreased (pD2 of 6.69 +/- 0.24 vs. 5.96 +/- 0.18) and there was some tendency for reduced venule sensitivity. These data suggest that exercise training in rats produces a decrease in alpha- or an increase in beta-adrenergic receptor sensitivity.

Pressor resistance to vasopressin in sodium depletion, potassium depletion, and cirrhosis

1986 ◽  
Vol 251 (3) ◽  
pp. R525-R530 ◽  
Author(s):  
B. M. Murray ◽  
M. S. Paller
Keyword(s):  
Pressor Response ◽  
Potassium Depletion ◽  
Pressor Effect ◽  
Sodium Depletion ◽  
Sprague Dawley ◽  
Low Sodium Diet ◽  
Low Sodium ◽  
Sprague Dawley Rats ◽  
Low Potassium ◽  
Baroreceptor Reflexes

Resistance to the pressor effects of angiotensin II, but not norepinephrine, has been observed in sodium depletion, potassium depletion, and cirrhosis. We tested the response to arginine vasopressin (AVP) in each of these conditions. Male Sprague-Dawley rats were made sodium depleted with furosemide and a low-sodium diet for 3 days, potassium depleted by feeding a low-potassium diet for 14-21 days, or cirrhotic by inhalation of carbon tetrachloride for 8 wk. In conscious rats, the pressor response to graded doses of AVP was reduced in sodium depletion by 27-43% compared with control rats. Sodium-depleted rats were also found to have enhanced baroreceptor reflexes, since the decrease in heart rate for a given increase in mean arterial pressure was greater than in control rats. When the ganglionic blocker pentolinium tartrate was given to sodium-depleted rats the pressor response to AVP was restored to control levels. In potassium-depleted rats the pressor response to AVP was 21-52% lower than that in controls, whereas cirrhotic rats also had a blunted response to AVP (14-41% lower than control). However, there was no evidence in either of these two states of enhanced baroreceptor activity, and pretreatment with pentolinium tartrate did not restore the pressor response to normal. Therefore, although resistance to the pressor effect of AVP was found in all three conditions, the mechanism of this effect was different in sodium depletion compared with potassium depletion and cirrhosis. We conclude that resistance to the pressor action of AVP in sodium depletion was secondary to resetting of the baroreceptors.

scholarly journals A 90-Day Oral (Dietary) Toxicity Study of Rebaudioside A in Sprague-Dawley Rats

2008 ◽  
Vol 27 (1) ◽  
pp. 65-80 ◽  
Author(s):  
Andrey I Nikiforov ◽  
Alex K Eapen
Keyword(s):  
Clinical Pathology ◽  
Stevia Rebaudiana ◽  
Rebaudioside A ◽  
Sprague Dawley ◽  
Small Magnitude ◽  
Stevia Rebaudiana Bertoni ◽  
Sprague Dawley Rats ◽  
The Difference ◽  
High Concentrations ◽  
And Behavior

Rebaudioside A is one of several glycosides found in the leaves of Stevia rebaudiana (Bertoni) Bertoni (Compositae) stevia that has been identified as a potential sweetener. The present study (initiated in April 2006 and completed in October 2006) evaluated the safety of this sweetener when administered as a dietary admix at target exposure levels of 500, 1000, and 2000 mg/kg/day to Sprague-Dawley rats for 90 days. There were no treatment-related effects on the general condition and behavior of the animals as determined by clinical observations, functional observational battery, and locomotor activity assessments. Evaluation of clinical pathology parameters revealed no toxicologically relevant, treatment-related effects on hematology, serum chemistry, or urinalysis. Macroscopic and microscopic findings revealed no treatment-related effects on any organ evaluated. Lower mean body weight gains were noted in males in the 2000 mg/kg/day group throughout the study, which was considered to be test article related; however, given the small magnitude of the difference as compared to controls, this effect was not considered to be adverse. Results of this study clearly demonstrate that dietary administration of high concentrations of rebaudioside A for 90 consecutive days to Sprague-Dawley rats was not associated with any signs of toxicity.

Hindbrain GRP receptor blockade antagonizes feeding suppression by peripherally administered GRP

1996 ◽  
Vol 271 (1) ◽  
pp. R180-R184 ◽  
Author(s):  
E. E. Ladenheim ◽  
J. E. Taylor ◽  
D. H. Coy ◽  
K. A. Moore ◽  
T. H. Moran
Keyword(s):  
Food Intake ◽  
Critical Role ◽  
Intraperitoneal Administration ◽  
Reduce Food Intake ◽  
Sprague Dawley ◽  
Glucose Intake ◽  
Sprague Dawley Rats ◽  
Feeding Effects ◽  
Grp Receptors ◽  
The Relationship

Bombesin (BN)-like peptides injected peripherally or centrally suppress food intake in rats. The relationship between the central and peripheral actions of BN is unknown. However, experimental evidence supports a critical role for the caudal hindbrain in mediating the feeding effects of BN. To investigate this relationship further, we examined the ability of fourth ventricular infusion of a specific gastrin-releasing peptide (GRP) antagonist, [D-F5, Phe6, D-Ala11]BN-(6-13) methyl ester (BN-ME), to block suppression of glucose intake (0.5 kcal/ml) produced by intraperitoneal administration of GRP-(18-27) in 5-h food-deprived male Sprague-Dawley rats (n = 10). We found that fourth ventricular administration of 10, 32, and 100 ng BN-ME blocked the suppression of glucose intake produced by peripherally administered 10 nmol/kg GRP-(18-27). The most effective dose of BN-ME (100 ng) blocked the ability of peripheral injection of GRP-(18-27) to inhibit glucose intake but had no effect on intake when given alone. These results demonstrate that the availability of caudal hindbrain GRP receptors is necessary for peripherally administered GRP-(18-27) to reduce food intake in rats.

Preference for nacl solutions in sham drinking Sprague-Dawley rats: Water deprivation, sodium depletion, and angiotensin II

1995 ◽  
Vol 57 (4) ◽  
pp. 753-757 ◽  
Author(s):  
Neil E. Rowland ◽  
Kenneth R. Morian ◽  
Tana M. Nicholson ◽  
Juanita J. Salisbury
Keyword(s):  
Angiotensin Ii ◽  
Water Deprivation ◽  
Sodium Depletion ◽  
Sprague Dawley ◽  
Sprague Dawley Rats
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