Hypothyroidism increases serotonin turnover and sympathetic activity in the adult rat

1991 ◽  
Vol 69 (2) ◽  
pp. 205-210 ◽  
Author(s):  
W. N. Henley ◽  
X. Chen ◽  
C. Klettner ◽  
L. L. Bellush ◽  
M. A. Notestine
Keyword(s):  
Recovery Period ◽  
Normalization Procedure ◽  
Sprague Dawley ◽  
Creatinine Excretion ◽  
Adult Rat ◽  
Sympathetic Function ◽  
Sham Surgery ◽  
Sprague Dawley Rats ◽  
Serotonin Turnover ◽  
Colonic Temperature

Adult, male Sprague–Dawley rats underwent surgical thyroidectomy (Tx) or sham surgery. In all three experiments from which data are reported, a 3-week recovery period was allowed. In experiments I and II, baseline measurements of colonic temperature (Tc) and urinary norepinephrine excretion (NE) were obtained, and both variables were monitored daily for the duration of the studies. After baseline measurements, half of each surgical group was given either triiodothyronine (T3) or vehicle injections subcutaneously; in experiment I replacements continued for 1.5 days, while in experiment II T3 replacement continued for 3.5 days. Rats were decapitated at the end of each experiment and serotonin (5-HT) turnover was measured in brainstem. Serotonin turnover in rostral and caudal brainstem was increased with Tx (p < 0.05). Increased turnover in caudal brainstem was normalized by T3 only in experiment II. Similarly, decreased Tc and elevated NE with Tx were normalized in experiment II but not in experiment I. In experiment III, NE measurements normalized on a creatinine excretion basis indicated that increased NE is evident with Tx, irrespective of normalization procedure. Significant correlations between 5-HT in caudal brainstem and metabolic correlates of sympathetic function, concurrent normalization of NE and 5-HT in caudal brainstem, plus work from other laboratories describing sympathoexcitatory serotonergic neurons located in me caudal brainstem suggest that the central and peripheral changes in me hypothyroid rat are causally related.Key words: triiodothyronine, norepinephrine, serotonin, brainstem, metabolism.

scholarly journals Transcriptomic Impact of IMA-08401, a Novel AHR Agonist Resembling Laquinimod, on Rat Liver

2019 ◽  
Vol 20 (6) ◽  
pp. 1370 ◽  
Author(s):  
Stephenie Prokopec ◽  
Raimo Pohjanvirta ◽  
Selma Mahiout ◽  
Lars Pettersson ◽  
Paul Boutros
Keyword(s):  
Recovery Period ◽  
Oxidative Stress Response ◽  
Sprague Dawley ◽  
Aryl Hydrocarbon ◽  
Sprague Dawley Rats ◽  
Low Toxicity ◽  
Repeated Dosing ◽  
Transcriptomic Changes ◽  
Subacute Exposure

IMA-08401 (C2) is a novel aryl hydrocarbon receptor (AHR) agonist and selective AHR modulator (SAHRM) that is structurally similar to laquinimod (LAQ). Both compounds are converted to the AHR-active metabolite DELAQ (IMA-06201) in vivo. SAHRMs have been proposed as therapeutic options for various autoimmune disorders. Clinical trials on LAQ have not reported any significant toxic outcomes and C2 has shown low toxicity in rats; however, their functional resemblance to the highly toxic AHR agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) raises questions. Here, we characterize the hepatic transcriptomic changes induced by acute (single-dose) and subacute exposure (repeated dosing for 5 days followed by a 5-day recovery period) to C2 in Sprague-Dawley rats. Exposure to C2 leads to activation of the AHR, as shown by altered transcription of Cyp1a1. We identify a heightened response early after exposure that drops off by day 10. Acute exposure to C2 leads to changes to transcription of genes involved in antiviral and antibacterial responses, which highlights the immunomodulator effects of this AHR agonist. Subacute exposure causes an oxidative stress response in the liver, the consequences of which require further study on target tissues such as the CNS and immune system, both of which may be compromised in this patient population.

Ontogeny of glycine transport in isolated rat renal tubules

1977 ◽  
Vol 233 (3) ◽  
pp. F241-F246
Author(s):  
K. S. Roth ◽  
S. M. Hwang ◽  
J. W. London ◽  
S. Segal
Keyword(s):  
Rat Kidney ◽  
Renal Tubules ◽  
Sprague Dawley ◽  
Entry Rate ◽  
Glycine Uptake ◽  
Adult Rat ◽  
High Affinity ◽  
Sprague Dawley Rats ◽  
Rate Kinetics ◽  
Isolated Renal Tubule

Isolated renal tubule preparations were made from newborn Sprague-Dawley rats and used to study initial entry rate kinetics of glycine. The results were compared to those obtained in the isolated tubule preparation from the adult rat kidney. While initial rates of glycine uptake were identical for newborn and adult tubules, significant differences in influx kinetics were demonstrated. Of the two apparent transport Km systems shown to be present in the newborn tubule, the high-affinity, low-capacity system accounts for about 40% of total glycine uptake at physiologic concentrations. The high-affinity, low-capacity system of the adult tissue accounts for about 10% of total uptake at the same concentration range. The data lend strength to the argument against the concept that the physiologic hyperglycinuria of the newborn rat is due to either impaired ability to concentrate glycine intracellularly or to absence of one or more transport mechanisms for glycine.

scholarly journals Evidences Suggesting that Distinct Immunological and Cellular Responses to Light Damage Distinguishes Juvenile and Adult Rat Retinas

2019 ◽  
Vol 20 (11) ◽  
pp. 2744
Author(s):  
Anna Polosa ◽  
Shasha Lv ◽  
Wassila Ait Igrine ◽  
Laura-Alexie Chevrolat ◽  
Hyba Bessaklia ◽  
...  
Keyword(s):  
Immune System ◽  
Light Exposure ◽  
Age Related Macular Degeneration ◽  
Light Damage ◽  
Sprague Dawley ◽  
Adult Rat ◽  
Age Related ◽  
Degenerative Disorders ◽  
Sprague Dawley Rats ◽  
Dose Dependent

To unravel the mechanisms behind the higher resistance to light damage of juvenile (JR) versus adult (AR) rats, Sprague Dawley rats were exposed to a bright luminous environment of 10, 000 lux. The light-induced retinopathy (LIR) was assessed with histology, electroretinography and immunohistochemistry (IHC). In JR, 2 days of exposure induced the typical LIR, while >3 days added little LIR. IHC revealed a subtle migration of microglia (Iba1 marker) from the inner to the outer retina after 3 days of exposure in JR contrasting with the stronger reaction seen after 1 day in AR. Similarly, in JR, the Müller cells expressed less intense GFAP, CNTF and FGF2 staining compared to AR. Our results suggest that in JR the degree of retinal damage is not proportional to the duration of light exposure (i.e., dose-independent retinopathy), contrasting with the dose-dependent LIR reported in AR. The immature immune system in JR may explain the delayed and/or weaker inflammatory response compared to AR, a finding that would also point to the devastating contribution of the immune system in generating the LIR phenotype, a claim also advanced to explain the pathophysiology of other retinal degenerative disorders such as Age-related Macular Degeneration, Diabetic Retinopathy and Retinitis Pigmentosa.

scholarly journals Glucocorticoids attenuate the central sympathoexcitatory actions of insulin

2014 ◽  
Vol 112 (10) ◽  
pp. 2597-2604 ◽  
Author(s):  
Jennifer L. Steiner ◽  
Megan E. Bardgett ◽  
Lawrence Wolfgang ◽  
Charles H. Lang ◽  
Sean D. Stocker
Keyword(s):  
Food Intake ◽  
Mammalian Target Of Rapamycin ◽  
Chronic Administration ◽  
Sprague Dawley ◽  
Sympathetic Function ◽  
Sprague Dawley Rats ◽  
Access To Water ◽  
The Central Nervous System ◽  
Regulate Food Intake ◽  
Few Data

Insulin acts within the central nervous system to regulate food intake and sympathetic nerve activity (SNA). Strong evidence indicates that glucocorticoids impair insulin-mediated glucose uptake and food intake. However, few data are available regarding whether glucocorticoids also modulate the sympathoexcitatory response to insulin. Therefore, the present study first confirmed that chronic administration of glucocorticoids attenuated insulin-induced increases in SNA and then investigated whether these effects were attributed to deficits in central insulin-mediated responses. Male Sprague-Dawley rats were given access to water or a drinking solution of the glucocorticoid agonist dexamethasone (0.3 μg/ml) for 7 days. A hyperinsulinemic-euglycemic clamp significantly increased lumbar SNA in control rats. This response was significantly attenuated in rats given access to dexamethasone for 7, but not 1, days. Similarly, injection of insulin into the lateral ventricle or locally within the arcuate nucleus (ARC) significantly increased lumbar SNA in control rats but this response was absent in rats given access to dexamethasone. The lack of a sympathetic response to insulin cannot be attributed to a generalized depression of sympathetic function or inactivation of ARC neurons as electrical activation of sciatic afferents or ARC injection of gabazine, respectively, produced similar increases in SNA between control and dexamethasone-treated rats. Western blot analysis indicates insulin produced similar activation of Akt Ser473 and rpS6 Ser240/244 in the ventral hypothalamus of control and dexamethasone-treated rats. Collectively, these findings suggest that dexamethasone attenuates the sympathoexcitatory actions of insulin through a disruption of ARC neuronal function downstream of Akt or mammalian target of rapamycin (mTOR) signaling.

scholarly journals A 90-day Sub-chronic Oral Toxicity Assessment of Mulberry Extract in Sprague Dawley Rats

2021 ◽  
Vol 58 ◽  
pp. 004695802110560
Author(s):  
Min Hong ◽  
Min Lu ◽  
Yimin Qian ◽  
Liping Wei ◽  
Yaqun Zhang ◽  
...  
Keyword(s):  
Clinical Chemistry ◽  
Recovery Period ◽  
Safety Evaluation ◽  
Toxicity Assessment ◽  
Sprague Dawley ◽  
Oral Toxicity ◽  
Renal Tubular Cells ◽  
Sprague Dawley Rats ◽  
Adverse Effect Level ◽  
Renal Tubular

Mulberry extract from Fructus Mori contains an anthocyanin pigment and has been widely used as a food additive in China and other Eastern Asian countries. Only few research has been done on toxicological profiling of mulberry extract for its safety evaluation; however, the data is inconclusive. In the current study, mulberry extract of 4200, 1400, or 466 mg/kg were orally administrated to Sprague Dawley rats for 90 consecutive days followed by a recovery period of 28 days. No abnormalities were detected in body weights, food intake, ophthalmological, hematological, coagulation, clinical chemistry, and organ weights parameters. Discoloration of urine (red, purple, and brown) and feces (black), along with bedding material (purple) were observed in the 4200 mg/kg group. Further, microscopic examination revealed brown granules in the renal tubular cells for rats in 4200 and 1400 mg/kg groups. Since these changes were associated with excretory effect of the extract, the No Observed Adverse Effect Level was determined to be 4200 mg/kg, which was equivalent to the 1058.5 mg/kg of anthocyanin.

Corticosterone-responsive and -unresponsive metabolic characteristics of adrenalectomized rats

1994 ◽  
Vol 267 (3) ◽  
pp. R799-R804 ◽  
Author(s):  
C. R. Hamelink ◽  
P. J. Currie ◽  
J. W. Chambers ◽  
T. W. Castonguay ◽  
D. V. Coscina
Keyword(s):  
Metabolic Pathways ◽  
Recovery Period ◽  
Fat Metabolism ◽  
Light Period ◽  
Preoperative Period ◽  
Sprague Dawley ◽  
Metabolic Characteristics ◽  
Sprague Dawley Rats ◽  
Postsurgical Recovery ◽  
Adrenalectomized Rats

Glucocorticoids are important in influencing substrate flux through the metabolic pathways. This study was designed to answer the question "Does adrenalectomy (ADX) cause a shift toward fat metabolism as measured by a decrease in respiratory quotient (RQ)?" Male Sprague-Dawley rats were divided into four groups, ADX, ADX + 20% corticosterone (Cort) (ADX-20%), ADX + 40% Cort (ADX-40%), or sham-operated controls (Sham). ADX-20% received 50 mg and ADX-40% 100 mg Cort dissolved in 250-mg cholesterol pellets and placed subcutaneously. Each rat was monitored for 90 min four times both during a preoperative period and again after a 1-wk postsurgical recovery period in an indirect calorimeter. Cort prevented ADX-induced suppression of weight gain and food intake. ADX decreased motoric activity in both the light and dark periods. Cort restored activity to Sham levels. ADX decreased RQ only in the dark (0.858 ADX vs. 0.891 Sham) and was reversed only in the ADX-40% group. Energy expenditure (EE) was depressed in both the light and dark by ADX; Cort partially restored EE to Sham values in the light period.

Relationship between sympathetic activity and diet-induced obesity in two rat strains

1983 ◽  
Vol 245 (3) ◽  
pp. R364-R371 ◽  
Author(s):  
B. E. Levin ◽  
J. Triscari ◽  
A. C. Sullivan
Keyword(s):  
Sympathetic Activity ◽  
Caloric Intake ◽  
Sprague Dawley ◽  
Rat Strains ◽  
Sympathetic Function ◽  
Diet Induced Obesity ◽  
Sprague Dawley Rats ◽  
Calorie Diet ◽  
High Calorie Diet ◽  
High Calorie

Chronic diet-induced obesity developed in 50-60% of male Sprague-Dawley rats fed a relatively high-calorie diet for 90 days. The remaining rats decreased their caloric intake and resisted the development of obesity. All male Fischer F-344 rats fed this diet for 85 days became obese but to only half the degree of the obese Sprague-Dawley rats. The development of chronic obesity in both rat strains was associated with decreased norepinephrine (NE) levels in hearts and aortas and decreased NE turnover in aortas compared with chow-fed controls. However, 40-50% of the Sprague-Dawley rats did not become obese on this diet, yet showed similar findings suggesting an effect of dietary composition on sympathetic function. The more profoundly obese Sprague-Dawley rats additionally showed decreased or absent NE turnover in their hearts and pancreases. Since sympathetic function in both strains of rats with diet-induced obesity was either depressed or normal, it appears unlikely that the initial enhancement of sympathetic activity seen during short-term overfeeding plays an important continuing role in combating more chronic states of obesity in the rat.

scholarly journals Simulated Aeromedical Evacuation in a Polytrauma Rat Model

2019 ◽  
Vol 90 (12) ◽  
pp. 1016-1025
Author(s):  
Françoise Arnaud ◽  
Georgina Pappas ◽  
Eric Maudlin-Jeronimo ◽  
Carl Goforth
Keyword(s):  
Rat Model ◽  
Recovery Period ◽  
White Blood Cells ◽  
Mass Casualties ◽  
Sprague Dawley ◽  
Aeromedical Evacuation ◽  
Risk Of Mortality ◽  
Sprague Dawley Rats ◽  
Combat Casualties ◽  
Volume Controlled

BACKGROUND: Hemorrhage and traumatic brain injury can be lethal if left unattended. The transportation of severely wounded combat casualties from the battlefield to higher level of care via aeromedical evacuation (AE) may result in unintended complications. This could become a serious concern at the time of evacuation of mass casualties or for prolonged field care scenarios with limited resources.METHODS: Following instrumentation (t1), anesthetized Sprague-Dawley rats were injured or not [75-kPa blast and 30% estimated blood-volume controlled hemorrhage] (t2). After 15 min, all rats were resuscitated with saline. During the simulated 3-h evacuation, 8000 ft (2440 m) vs. sea-level heart rate, temperature, and oxygenation (Spo2) were continuously recorded. One group of rats was euthanized immediately after evacuation (t3) and another after a 72-h recovery period (t4). Hematology and metabolic levels were measured at t1, t2, t3, and t4.RESULTS: Survival was 100% in control-uninjured animals, 83% in injured animals under normobaria, and significantly reduced to 50% under hypobaria. This AE setting resulted in significantly lower hemodynamics, thermoregulation, and oxygenation parameters in the animals under hypobaria than those under normobaria. The initial lower mean arterial pressure (MAP) with the reduced oxygen level before AE were critical factors for the survival of injured animals. We observed a general increase of white blood cells and platelet ability to aggregate at t4 in all experimental groups.CONCLUSION: Physiological parameters were affected during aeromedical evacuation in all groups. This was worsened for injured animals with MAP less than 60 mmHg associated with low Spo2 in a simulated aeromedical evacuation. This represented a high risk of mortality for severely polytraumatized animals.Arnaud F, Pappas G, Maudlin-Jeronimo E, Goforth C. Simulated aeromedical evacuation in a polytrauma rat model. Aerosp Med Hum Perform. 2019; 90(12):1016–1025.

scholarly journals Juvenile toxicity study of Gossence™ (galactooligosaccharides) in Sprague Dawley rats

2020 ◽  
Vol 4 ◽  
pp. 239784732091321
Author(s):  
Manish Jain ◽  
Moninder Kaur ◽  
Deepika Pandey Tiwari ◽  
Chandrashekara Vishwanath ◽  
Nataraju Javaregowda ◽  
...  
Keyword(s):  
Clinical Chemistry ◽  
Pediatric Population ◽  
Recovery Period ◽  
Clinical Signs ◽  
Weighted Average ◽  
Organ Weight ◽  
High Dose ◽  
Average Dose ◽  
Sprague Dawley ◽  
Sprague Dawley Rats

Gossence™ (galactooligosaccharide; GOS) is a prebiotics and used as one of the major constituents in infant milk formulas that act as a functional food. Gossence is manufactured by Tata Chemicals Ltd, India, through a patented process of biotransformation of lactose. A toxicology study in juvenile rats was carried out to assess the safety profile of Gossence intended for pediatric population. The objective of this study is to assess the potential systemic toxicity of Gossence when administered through gavage at dose levels of 1000, 2000, or 5000/3000 mg/kg/day (equivalent to 1347, 2694, and 6735/4041 mg/kg/day of GOS, respectively) to juvenile Sprague Dawley rats from postnatal day (PND) 4 to PND 52 (i.e. total 49 days of dosing period). A separate group of animals were treated with vehicle (purified Milli Q water) for a similar duration. The following parameters were evaluated during the study period: morbidity/mortality check, clinical signs, body weights, body weight changes, food consumption, functional observational battery, motor activity, postnatal developmental observations, hematology, clinical chemistry, urinalysis, organ weight, gross pathology, and histopathology. During dosing phase, the high-dose group, 5000 mg/kg/day, was reduced to 3000 mg/kg/day (equivalent to 4041 mg/kg/day dose of GOS) from day 16 (PND 19) onward, due to clinical signs of watery feces and yellow color stains at urogenital region and mortality in two animals on day 15 (PND 18) of the study. Time-weighted average dose for 5000 mg/kg/day was equivalent to 3600 mg/kg/day. No further deaths or clinical signs were noticed in animals at 3000 mg/kg/day from day 18 (PND 21) of dosing phase to until terminal euthanization. At the terminal euthanization, there were no test item-related gross changes observed in all surviving rats except for, an increased cecum size in some of the rats at 5000/3000 mg/kg/day, which correlated with the increased weights of cecum with contents during organ weight recording, but this had no correlating light microscopic changes during histological examination. The cecal enlargement was completely recovered following the 14-day recovery period. The no-observedadverse-effect level is 3000 mg/kg/day for Gossence, which is equivalent to 4041 mg/kg/day of GOS in both sexes.

Toxic Peripheral Neuropathy with Demyelination in Sprague-Dawley Rats Given CGS 21595 —A 5-Lipoxygenase Inhibitor

1992 ◽  
Vol 29 (2) ◽  
pp. 145-151 ◽  
Author(s):  
D. E. Gunson ◽  
P. S. Sahota ◽  
W. O. Iverson ◽  
R. Y. Chau ◽  
G. M. McCormick ◽  
...  
Keyword(s):  
Peripheral Neuropathy ◽  
Recovery Period ◽  
Female Rats ◽  
Male Rats ◽  
Renal Tubules ◽  
Sprague Dawley ◽  
Lipoxygenase Inhibitor ◽  
Male And Female ◽  
Male And Female Rats ◽  
Sprague Dawley Rats

Male and female Sprague-Dawley rats were given CGS 21595, a pro-drug that is almost immediately metabolized to CGS 19213, a naphthoquinone that acts as a 5-lipoxygenase inhibitor. The compound was administered by gavage to five groups of Sprague-Dawley rats (group Nos. 1, 5, n = 30; group Nos. 2–4, n = 20) at daily doses of 0, 50, 150, 500, or 1,000 mg/kg for 13 weeks. Rats in the higher dose groups had a reduced weight gain, but significant neurologic signs were not observed. A peripheral neuropathy consisting predominantly of myelin destruction in the spinal nerve roots and sciatic nerves was seen in male rats treated with ≥ 150 mg/kg CGS 21595 and in female rats treated with ≥50 mg/kg CGS 21595 for 13 weeks. This lesion was not fully reversible after a recovery period of 4 weeks. Lesions consisted of ballooning of myelin sheaths, infiltration by macrophages, demyelination, and occasional areas of remyelination. Axons were generally preserved, and the brain and spinal cord were not affected. Male and female rats in all treatment groups had cytoplasmic hyaline droplets in the proximal renal tubules. This change was reversible after 4 weeks and was not associated with any other adverse effects on the kidney.

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