Glucocorticoid Abnormalities in Female Rats Exposed to a Predator-Based Psychosocial Stress Model of PTSD

People with post-traumatic stress disorder (PTSD) exhibit heightened anxiety and enhanced negative feedback of the hypothalamus-pituitary-adrenal (HPA) axis. We previously reported that male rats exposed to a predator-based psychosocial stress model of PTSD exhibited comparable changes in anxiety-like behavior and HPA axis activity, including lower baseline levels of corticosterone and a greater suppression of corticosterone after dexamethasone administration. Here, we assessed whether we would observe similar effects in female rats exposed to this model. Adult female Sprague-Dawley rats were exposed to a cat on two occasions (separated by 10 days), in combination with chronic social instability. Three weeks after the second cat exposure, we assessed anxiety-like behavior on an elevated plus maze (EPM) and collected blood samples from rats in the absence or presence of dexamethasone to quantify serum corticosterone levels. Although stressed females did not display heightened anxiety on the EPM, they exhibited significantly lower overall corticosterone levels and a greater suppression of corticosterone after dexamethasone administration. The observation of significantly lower overall corticosterone levels in stressed females was replicated in a separate, independent experiment. These findings suggest that the predator-based psychosocial stress model of PTSD may be useful for studying mechanisms that underlie changes in HPA axis function in females exposed to trauma.

Download Full-text

Sexual dimorphism in vasopressin-induced contraction of rat aorta

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1991.260.2.h453 ◽

1991 ◽

Vol 260 (2) ◽

pp. H453-H458 ◽

Cited By ~ 21

Author(s):

J. N. Stallone ◽

J. T. Crofton ◽

L. Share

Keyword(s):

Estrous Cycle ◽

Vascular Reactivity ◽

Rat Aorta ◽

Isometric Tension ◽

Female Rats ◽

Male Rats ◽

Maximal Response ◽

Sprague Dawley ◽

Tension Development ◽

Sprague Dawley Rats

Previously, we reported that, in the rat, pressor responsiveness to vasopressin (VP) is higher in males than in females during most phases of the estrous cycle. To explore the role of the vasculature in this phenomenon, we examined vascular reactivity to VP in thoracic aortas of male rats and female rats during each phase of the estrous cycle. Aortic rings were prepared from age-matched male and female Sprague-Dawley rats and mounted for isometric tension recording. Maximal response of female aortas to VP (4,246 +/- 163 mg/mg ring dry wt) was more than twice (P less than 0.001) that of male aortas (1,877 +/- 215 mg/mg ring wt). Sensitivity of female aortas to VP was substantially higher (P less than 0.001) than that of male aortas (EC50: 10.9 +/- 0.7 vs. 19.0 +/- 1.6 nM, respectively). Maximal rate of tension development (dT/dtmax) during contraction with VP was nearly twofold higher (P less than 0.01) in female aortas (536 +/- 23 mg/min) than in male aortas (300 +/- 19 mg/min). Maximal response, sensitivity, and dT/dtmax of female aortas did not vary significantly during the estrous cycle. Maximal response of female aortas to phenylephrine (PE; 1,251 +/- 93 mg/mg ring wt) was half that (P less than 0.001) of male aortas (2,546 +/- 194 mg/mg ring wt); sensitivity to PE did not differ significantly (EC50: 0.33 +/- 0.02 vs. 0.38 +/- 0.06 microM, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Download Full-text

Some nutritional properties of unrefined sugar and its promotion of the survival of new-born rats

British Journal Of Nutrition ◽

10.1079/bjn19850146 ◽

1985 ◽

Vol 54 (3) ◽

pp. 593-603 ◽

Cited By ~ 4

Author(s):

Eisa Omer Ahmed ◽

Yudkin John

Keyword(s):

Fatty Acid Synthetase ◽

Female Rats ◽

Male Rats ◽

Blood Cholesterol ◽

Maize Starch ◽

Sprague Dawley ◽

Brown Sugar ◽

Sprague Dawley Rats ◽

Male Wistar Rats ◽

Glucose 6 Phosphate Dehydrogenase

1. The claims that rats fed on diets with ‘brown sugar’ (unrefined muscovado) perform better in a number of ways than do rats fed on refined white sugar (sucrose) have been examined.2. Male Wistar rats were fed on purified diets from weaning, in which the carbohydrate component was either maize starch or unrefined sugar or sucrose. The sugars produced no differences in growth rate, body composition, or the weights of liver or kidneys. Compared with sucrose, unrefined sugar produced an increase in blood cholesterol and in the activity of hepatic fatty acid synthetase, and a greater increase in blood triglyceride. In confirmation of earlier results, rats fed on either sugar had heavier livers and kidneys, increased activity of hepatic glucose-6-phosphate dehydrogenase (EC 1.1.1.49) and a higher concentration of plasma triglyceride compared with rats fed on maize starch.3. Female Sprague-Dawley rats were fed on the same three diets as the male rats, and mated when they weighed about 200 g. No difference was seen in their ability to mate, the progress of pregnancies, or the sizes of the litters. Does fed on unrefined sugar produced litters of higher viability than did does fed on starch or sucrose. Survival was between 85 and 100% with unrefined sugar and between 30 and 75% with starch or sucrose.4. Unrefined muscovado sugar has thus been shown to contain a factor required by female rats for the proper viability of their pups. This may be the same ‘Reproductive Factor R’ as that described by Wiesner & Yudkin (1951). In certain circumstances, unrefined muscovado sugar might therefore contribute to the nutritional value of a human diet, although in what circumstances, in what respect and to what extent it might do so, is by no means clear.

Download Full-text

Intraperitoneal Alfaxalone and Alfaxalone–Dexmedetomidine Anesthesia in Sprague–Dawley Rats (Rattus norvegicus)

Journal of the American Association for Laboratory Animal Science ◽

10.30802/aalas-jaalas-19-000161 ◽

2020 ◽

Vol 59 (5) ◽

pp. 531-538

Author(s):

Sylvia E West ◽

Jonathan C Lee ◽

Tinika N Johns ◽

Elizabeth A Nunamaker

Keyword(s):

Rattus Norvegicus ◽

Female Rats ◽

Male Rats ◽

Sprague Dawley ◽

Male And Female ◽

Withdrawal Reflex ◽

Male And Female Rats ◽

Sprague Dawley Rats ◽

Laboratory Rodent ◽

Physiologic Parameters

Due to their unpredictability and variable effects, injectable anesthetic regimens in laboratory rodent species warrant refinement. In our study we sought to evaluate alfaxalone, which has gained recent popularity in veterinary medicine, alone and in combination with dexmedetomidine to evaluate their anesthetic ability in Sprague–Dawley rats when administered intraperitoneally. Three doses of alfaxalone only and 4 dose combinations of alfaxalone-dexmedetomidine were tested in males and female rats. The time to induction, anesthetic duration, pulse rate, respiratory rate, temperature, and time to recovery were recorded by a blind observer. The level of anesthesia induced by the various anesthetic protocols was assessed by using pedal withdrawal reflex to a noxious stimulus and scored according to the response. Dependent on the treatment group, atipamezole or saline was administered intraperitoneally once animals reached 60 min of anesthesia. Regardless of the dose, alfaxalone alone achieved only a sedative level of anesthesia, whereas all alfaxalone-dexmedetomidine combinations led to a surgical level of anesthesia in all animals. Anesthesia regimens using alfaxalone alone and in combination with dexmedetomidine demonstrated sex-associated differences, with female rats maintaining longer durations of sedation or anesthesia than their male counterparts. Both male and female rats displayed decreases in physiologic parameters consistent with the effects of dexmedetomidine. Given the results described herein, we recommend 20 mg/kg alfaxalone for sedation and 30 mg/kg alfaxalone combined with 0.05 mg/kg dexmedetomidine for surgical anesthesia in female rats. Appropriate doses of alfaxalone only and alfaxalone-dexmedetomidine for male rats were not determined in this study and need further evaluation.

Download Full-text

7,8-Dihydroxyflavone Enhances Cue-Conditioned Alcohol Reinstatement in Rats

Brain Sciences ◽

10.3390/brainsci10050270 ◽

2020 ◽

Vol 10 (5) ◽

pp. 270 ◽

Cited By ~ 1

Author(s):

Samuel J. Hogarth ◽

Elvan Djouma ◽

Maarten van den Buuse

Keyword(s):

Body Weight ◽

Progressive Ratio ◽

Ethanol Exposure ◽

Ethanol Solution ◽

Female Rats ◽

Male Rats ◽

Sprague Dawley ◽

Self Administration ◽

Bdnf Expression ◽

Sprague Dawley Rats

Alcohol use disorder (AUD) is a detrimental disease that develops through chronic ethanol exposure. Reduced brain-derived neurotrophic factor (BDNF) expression has been associated with AUD and alcohol addiction, however the effects of activation of BDNF signalling in the brain on voluntary alcohol intake reinstatement and relapse are unknown. We therefore trained male and female Sprague Dawley rats in operant chambers to self-administer a 10% ethanol solution. Following baseline acquisition and progressive ratio (PR) analysis, rats were split into drug and vehicle groups during alcohol lever extinction. The animals received two weeks of daily IP injection of either the BDNF receptor, TrkB, agonist, 7,8-dihydroxyflavone (7,8-DHF), or vehicle. During acquisition of alcohol self-administration, males had significantly higher absolute numbers of alcohol-paired lever presses and a higher PR breakpoint. However, after adjusting for body weight, the amount of ethanol was not different between the sexes and the PR breakpoint was higher in females than males. Following extinction, alcohol-primed reinstatement in male rats was not altered by pretreatment with 7,8-DHF when adjusted for body weight. In contrast, in female rats, the weight-adjusted potential amount of ethanol, but not absolute numbers of active lever presses, was significantly enhanced by 7,8-DHF treatment during reinstatement. Analysis of spontaneous locomotor activity in automated photocell cages suggested that the effect of 7,8-DHF was not associated with hyperactivity. These results suggest that stimulation of the TrkB receptor may contribute to reward craving and relapse in AUD, particularly in females.

Download Full-text

Abstract 386: Compound 21 Induces Natriuresis via Renal AT2 Receptor Activation in Male and Female Rats

Hypertension ◽

10.1161/hyp.60.suppl_1.a386 ◽

2012 ◽

Vol 60 (suppl_1) ◽

Author(s):

Brandon A Kemp ◽

Nancy L Howell ◽

Robert M Carey

Keyword(s):

Receptor Activation ◽

Female Rats ◽

Male Rats ◽

Sprague Dawley ◽

Male And Female ◽

Male And Female Rats ◽

Sprague Dawley Rats ◽

Angiotensin Iii ◽

Compound 21 ◽

Renal Cortical Interstitium

Endogenous renal des-aspartyl 1 -angiotensin II (angiotensin III) activates renal proximal tubule AT 2 receptors (AT 2 Rs) and induces natriuresis via a nitric oxide-cyclic GMP signaling pathway. The present study explores the ability of highly selective non-peptide AT 2 R agonist Compound 21 (C21) to induce natriuresis. Sprague-Dawley rats (12 weeks old; male N=22; female N=18) were studied in the presence and absence of concurrent 24-h AT 1 R blockade with candesartan (CAND;0.01 mg/kg/min). Rats were anesthetized with Inactin 100 mg/kg i.p., uninephrectomized and instrumented for delivery of 3 cumulative 30-min i.v. infusions of C21 (100, 200, and 300 ng/kg/min) following a 30-min control infusion of vehicle. Mean arterial pressure (MAP) was measured for all periods and urine Na + excretion rate (U Na V) was calculated for the control and final C21 collection periods. To determine whether the systemically induced natriuresis is mediated by renal AT 2 Rs, PD-123319 (PD), a specific AT 2 R antagonist, was infused directly into the renal cortical interstitium(20 μg/kg/min and 10 μg/kg/min for females and males, respectively) during the i.v. C21 infusions. In female rats, C21 increased U Na V from 1.5 ± 0.20 to 7.48 ± 0.95 μmol/min (P<0.0001). This response was abrogated by concurrent intrarenal PD infusion [control 0.74 ± 0.19 vs. C21 2.02 ± 0.50 μmol/min (P<0.001from C21 alone). Systemic CAND administration augmented the natriuretic response to C21 [control 1.29 ± 0.25 vs. C21 10.68 ± 0.70 μmol/min (P<0.05 from C21 alone)]. In male rats, C21 increased U Na V from 0.46 ±0.08 to 6.21 ± 1.33 μmol/min (P<0.01). This response was blocked by concurrent intrarenal PD infusion [control 0.39 ± 0.11 vs. C21 1.69 ± 0.53 μmol/min (P<0.05 from C21 alone). Systemic CAND did not significantly alter the natriuretic response to C21 alone [control 0.49 ± 0.15 vs. C21 7.67 ± 0.72 μmol/min (P = NS from C21 alone). In female rats, CAND augmented the natriuretic response to C21 over that of male rats (P<0.01). Systemic arterial pressures were decreased by CAND in both male and female rats but were unchanged by C21 alone or together with intrarenal PD. C21 induces natriuresis via renal AT 2 R activation in both male and female rats. These data suggest the potential for AT 2 R agonist therapy in hypertension.

Download Full-text

Effects of endocrine disruptor furan on reproductive physiology of Sprague Dawley rats: An F1 Extended One-Generation Reproductive Toxicity Study (EOGRTS)

Human & Experimental Toxicology ◽

10.1177/0960327120911416 ◽

2020 ◽

Vol 39 (8) ◽

pp. 1079-1094 ◽

Cited By ~ 1

Author(s):

H Rehman ◽

S Jahan ◽

I Ullah ◽

P-O Thörnqvist ◽

M Jabbar ◽

...

Keyword(s):

Reproductive Toxicity ◽

Head Tilt ◽

Treated Group ◽

Toxicity Study ◽

Female Rats ◽

Male Rats ◽

Sprague Dawley ◽

Sprague Dawley Rats ◽

Estrous Cyclicity ◽

F1 Generation

The present study investigated the reproductive toxicity of furan in an Extended One-Generation Reproductive Toxicity Study in rats. Sprague Dawley F0 weaning rats (30 per sex per group) were exposed to furan orally at 0, 1, 2.5, 5, and 10 mg kg−1 for 10 weeks (males) and 2 weeks (females) and then mated. Results of F0 indicated that in the furan-treated groups (5 mg kg−1 and 10 mg kg−1), body weight (bw) gain decreased during prebreed and gestational period while increased during lactation periods. F0 animals prebreeding exposure resulted in head tilt and foot splay at 10 mg kg−1. Number of live pups at birth were decreased ( p < 0.001) at 10 mg kg−1. At postnatal day (PND) 70, a significant ( p = 0.03) decrease in testosterone levels of male rats and estrogen levels of female rats ( p = 0.05) was observed in 10 mg kg−1 furan-treated group in F1 generation. Luteinizing hormone, follicle-stimulating hormone, and progesterone levels were also reduced, but their reduction was not statistically significant in all groups. In higher dose furan group (10 mg kg−1), testicular and ovarian weights were reduced in F1 generation at PND 70, with decreased daily sperm production ( p = 0.01) and disturbed estrous cyclicity ( p < 0.01). Some histopathological changes were also observed in testis and ovaries in groups whose parents were previously exposed to 10 mg kg−1 bw of furan group. Based on the above results, it is suggested that exposure to food-based contaminant furan induced remarkable changes in the F0 (parental stage) and F1 (offspring, pubertal, and adult stage) generations of Sprague Dawley rats.

Download Full-text

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

Veterinary Pathology ◽

10.1177/030098589202900207 ◽

1992 ◽

Vol 29 (2) ◽

pp. 145-151 ◽

Cited By ~ 2

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.

Download Full-text

A Subchronic Toxicity Study of Phosflex 51B in Sprague-Dawley Rats

International Journal of Toxicology ◽

10.1080/109158101753253009 ◽

2001 ◽

Vol 20 (5) ◽

pp. 269-274 ◽

Cited By ~ 1

Author(s):

Ralph I. Freudenthal ◽

David Brandwene ◽

Welmoed Clous

Keyword(s):

Food Consumption ◽

Clinical Chemistry ◽

Female Rats ◽

Male Rats ◽

High Dose ◽

Sprague Dawley ◽

Significant Treatment ◽

Sprague Dawley Rats ◽

The Mean ◽

Microscopic Pathology

Phosflex 51B is a flame retardant plasticizer that is blended with polyvinyl chloride films to effectively control product flammability. Its composition places it in the butylated triphenyl phosphate category. Previous studies have shown Phosflex 51B to have low acute toxicity, to lack teratogenic and mutagenic activity, and to not induce delayed peripheral neuropathy. The present study was conducted to determine the toxicity of Phosflex 51B after repeated dietary exposure. Four groups, each consisting of 20 male and 20 female Sprague-Dawley rats, received rodent diet containing either 0, 100, 400, or 1600 ppm for 90 days. Parameters measured include body weight, food consumption, clinical observations, hematology, clinical chemistry, and cholinesterase activity. Tissues were examined at necropsy for gross changes and were processed for microscopic pathology. There were no significant treatment-related effects on body weights, food consumption, hematology and clinical chemistry, or cholinesterase values. A significant increase was observed in the absolute and relative mean weights of livers in high-dose male rats, the mean relative fiver weights of the high-dose female animals, the mean relative kidney weights of the high-dose male rats, and the mean absolute weights of the adrenal glands from high-dose female rats. Neither gross nor microscopic pathology examinations revealed tissue changes in these organs or in any other organs. Although increases in fiver, kidney, and adrenal weights were observed in certain animals in the 1600-ppm high-dose group, the administration of Phosflex 51B did not result in significant treatment-related adverse effects at dietary dose levels of 100 and 400 ppm. The no-observable-effect level (NOEL) in this study is 400 ppm.

Download Full-text

Effects of Curcumin on Bioavailability of Dioxin-Like Pollutants in Rats

10.21203/rs.3.rs-275821/v1 ◽

2021 ◽

Author(s):

Delei Cai ◽

Qing Chen ◽

Jianlong Han ◽

Yanhua Song ◽

Zhen Meng ◽

...

Keyword(s):

Chemical Structure ◽

Intestinal Epithelial Cells ◽

Female Rats ◽

Male Rats ◽

Intestinal Epithelial ◽

Sprague Dawley ◽

Sprague Dawley Rats ◽

Similar Chemical ◽

Small Intestinal ◽

Detoxification Mechanisms

Abstract In this study, we used Sprague–Dawley rats to observe the intervention effects of curcumin on bioavailability of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs). We reported the bioavailability of tetra- to hexa-chlorinated PCDD/Fs rose gradually, while that of hepta- and octa-chlorinated PCDD/Fs declined, and no obvious change was found in the bioavailability of DL-PCBs. Curcumin markedly reduced the toxic equivalent (TEQ) of PCDD/Fs in rats, illustrating it might competitively inhibit absorption of PCDD/Fs in small intestinal epithelial cells due to the similar chemical structure (diphenyl) between curcumin and PCDD/Fs. Moreover, curcumin was capable of lowering the TEQ of DL-PCBs in the liver of male rats, but caused no changes in female rats. In conclusion, the prominent decline in the bioavailability of PCDD/Fs and DL-PCBs induced by curcumin may serve as one of the detoxification mechanisms of curcumin for these pollutants.

Download Full-text

Dietary Exposure to Oxidized Frying Oil from Fetus to Adulthood Suppresses Male Reproductive Development by Altering Testicular Cholesterol and Testosterone Homeostasis in Sprague Dawley Rats

Journal of Nutrition ◽

10.1093/jn/nxaa091 ◽

2020 ◽

Vol 150 (7) ◽

pp. 1713-1721

Author(s):

Hai-Ping Wu ◽

Yu-Shun Lin ◽

Chi-Fen Chang ◽

Shui-Yuan Lu ◽

Pei-Min Chao

Keyword(s):

Weight Loss ◽

Body Weight ◽

Soybean Oil ◽

Body Weight Loss ◽

Reproductive Development ◽

Frying Oil ◽

Female Rats ◽

Male Rats ◽

Sprague Dawley ◽

Sprague Dawley Rats

ABSTRACT Background Dietary frying oil may have endocrine-disrupting effects, as a feminization effect was observed in cohorts of C57BL/6J male mice fetuses from dams consuming oxidized frying oil (OFO) during pregnancy. Objective The aim of present study was to test the hypothesis that OFO is an anti-androgen. Methods In experiment 1, male progeny of Sprague Dawley female rats fed fresh oil or an OFO diet (10 g fat/100 g, from fresh or 24-h–fried soybean oil; [control diet (C) and OFO groups, respectively] from midgestation through lactation were studied. Pups were weaned at 3 wk of age and then consumed their mothers’ diet until 9 wk of age. In addition, a group of dams and pups that consumed a high-fat diet (HF; 10 g fried and 20 g fresh soybean oil/100 g) was included to counteract body-weight loss associated with OFO ingestion. Indices of male reproductive development and testosterone homeostasis were measured. In experiment 2, male rats were allocated to C and OFO groups (treated as above) and indices of male fertility compared at 9–10 wk of age. Results In experiment 1, final body weights of the HF group were lower (17%) than the C group but higher (14%) than the OFO group (P < 0.0001 for each). In addition to abnormalities in seminiferous tubules, HF and OFO groups did not differ from one another, but, compared with the C group, had delayed preputial separation (4.9 d) and reductions in serum testosterone concentrations (17–74%), anogenital distance (8–20%), weights of androgen-dependent tissues (8–30%), testicular testosterone and cholesterol concentrations (30–40%), and mRNA levels of genes involved in steroidogenesis and cholesterol homeostasis (30–70%). In experiment 2, OFO-exposed males had 20% lower sperm motility (P < 0.05); however, when mated to normal females, pregnancy rates and litter sizes did not differ between OFO and C groups. Conclusions The anti-androgenic effect of OFO in Sprague Dawley rats was attributed to decreased testicular concentrations of cholesterol (testosterone precursor) and not body-weight loss.

Download Full-text