Influence of housing conditions from weaning to adulthood on the ventilatory, thermoregulatory, and endocrine responses to hypoxia of adult female rats

2012 ◽  
Vol 112 (9) ◽  
pp. 1474-1481 ◽  
Author(s):  
Sébastien Fournier ◽  
Richard Kinkead ◽  
Vincent Joseph
Keyword(s):  
Maternal Separation ◽  
Plasma Corticosterone ◽  
Female Rats ◽  
Male Rats ◽  
Whole Body ◽  
Housing Conditions ◽  
Juvenile Period ◽  
Hypoxic Conditions ◽  
Fraction Of Inspired Oxygen ◽  
The Impact

Housing conditions affect animal physiology. We previously showed that the hypoxic ventilatory and thermoregulatory responses to hypoxia of adult male rats housed in triads during the juvenile period (postnatal day 21 to adulthood) were significantly reduced compared with animals housed in pairs. Because sex hormones influence development and responsiveness to environmental stressors, this study investigated the impact of housing on the respiratory and thermoregulatory physiology of female rats. Since neonatal stress attenuates the hypoxic ventilatory response (HVR) of female rats at adulthood, experiments were performed both on “control” (undisturbed) animals and rats subjected to neonatal maternal separation (NMS; 3 h/day, postnatal days 3–12). At adulthood, ventilatory activity was measured by whole body plethysmography under normoxic and hypoxic conditions [fraction of inspired oxygen (FiO2) = 0.12; 20 min]. The ventilatory and body temperature responses to hypoxia of female rats raised in triads were reduced compared with rats housed in pairs. Housing female rats in triads did not affect basal or hypoxic plasma corticosterone levels but did increase levels of estradiol significantly. We conclude that modest changes in housing conditions (pairs vs. triads) from weaning to adulthood does influence basic homeostatic functions such as temperature and respiratory regulation. Triad housing can reverse the manifestations of respiratory instability at adulthood induced by stressful neonatal treatments. This should raise awareness of the benefits of increasing social interactions in clinical settings but also caution researchers of the potential impact of such subtle changes on experimental protocols and interpretation of results.

Influence of juvenile housing conditions on the ventilatory, thermoregulatory, and endocrine responses to hypoxia of adult male rats

2011 ◽  
Vol 111 (2) ◽  
pp. 516-523 ◽  
Author(s):  
Sébastien Fournier ◽  
Vincent Joseph ◽  
Richard Kinkead
Keyword(s):  
Adult Male ◽  
Maternal Separation ◽  
Corticosterone Level ◽  
Plasma Corticosterone ◽  
Male Rats ◽  
Whole Body ◽  
Housing Conditions ◽  
Juvenile Period ◽  
Hypoxic Conditions ◽  
Respiratory Plasticity

“Extreme” housing conditions, such as isolation (single housing) or crowding, are stressful for rats, and their deleterious impact on behavior is well documented. To determine whether more subtle variations in housing can affect animal physiology, the present study tested the hypothesis that the hypoxic ventilatory response (HVR) of adult male rats housed in pairs during the juvenile period (postnatal day 21 to adulthood) does not differ from that of animals housed in triads. Because neonatal stress augments the neuroendocrine responsiveness to stress and HVR, experiments were performed both on “control” (undisturbed) animals and rats subjected to neonatal maternal separation (NMS; 3 h/day, postnatal days 3–12). At adulthood, ventilatory activity was measured by whole body plethysmography under normoxic and hypoxic conditions (inspired fraction of O2 = 0.12; 20 min). The ventilatory and body temperature responses to hypoxia of rats raised in triads were less than those of rats housed in pairs. For the HVR, however, the attenuation induced by triad housing was more important in NMS rats. Triad housing decreased “basal” plasma corticosterone, but increased estradiol and testosterone levels. Much like the HVR, housing-related decrease in corticosterone level was greater in NMS than control rats. We conclude that modest changes in housing conditions (pairs vs. triads) during the juvenile period can influence basic homeostatic functions, such as temperature, endocrine, and respiratory regulation. Housing conditions can influence (even eliminate) the manifestations of respiratory plasticity subsequent to deleterious neonatal treatments. Differences in neuroendocrine function likely contribute to these effects.

scholarly journals Pregnancy and Lactation Alter Vitamin A Metabolism and Kinetics in Rats under Vitamin A-Adequate Dietary Conditions

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 120-120
Author(s):  
Yaqi Li ◽  
Ayasa Tajima ◽  
Floyd Mattie ◽  
Erin Dexheimer ◽  
Elizabeth Soucy ◽  
...  
Keyword(s):  
Vitamin A ◽  
Female Rats ◽  
Male Rats ◽  
Whole Body ◽  
Physiological Status ◽  
Female Rat ◽  
Plasma Fraction ◽  
Pregnancy And Lactation ◽  
The Impact ◽  
Mated Female

Abstract Objectives We investigated the impact of pregnancy and lactation on vitamin A (VA) metabolism and kinetics in rats, hypothesizing that this changed physiological status would perturb whole-body VA kinetics. Such information may be informative for future dietary recommendations. Methods Ten female rats (7 wk of age) and 6 male rats (9 wk of age) were fed an AIN-93 G diet upon arrival. After 1 week of acclimation, female rats received an oral dose of 3H-labeled retinol as the tracer to initiate the kinetic study. On d 21 after dosing (when 3H-retinol was expected to reach a log-linear terminal slope), 6 female rats were mated and checked daily for a vaginal plug to determine the date of pregnancy. On the day of delivery, litter size was adjusted to 10 pups/dam. Serial blood samples were collected from each female rat at 27–28 time points after dose administration until dams and pups were euthanized on d 14 of lactation. Hematocrit was measured, plasma tracer level was determined, and plasma fraction of dose vs. time was plotted. Model-based compartmental analysis will be applied to the plasma tracer data to develop VA kinetic models. Results All mated female rats became pregnant (pregnant group, PG, n = 6). Non-mated female rats were studied as non-pregnant controls (CN, n = 4). No difference was observed in hematocrit between PG and CN rats, suggesting no significant change in plasma volume expansion. Before breeding, plasma tracer response profiles were similar to CN rats. However, a consistent decline in plasma tracer levels was observed in PG rats during the middle of pregnancy, followed by a rise in late pregnancy, whereas such a change did not occur in CN rats. Moreover, during lactation, PG rats exhibited a steeper terminal slope compared to CN rats, indicating a more rapid utilization of VA in these lactating rats. Conclusions Pregnancy and lactation resulted in altered VA metabolism and kinetics in rats. Further analysis using mathematical modeling will explore the changes in kinetic parameters that underlie the perturbations we have observed in VA kinetics. Funding Sources National Institutes of Health.

Neonatal stress affects the aging trajectory of female rats on the endocrine, temperature, and ventilatory responses to hypoxia

2015 ◽  
Vol 308 (7) ◽  
pp. R659-R667 ◽  
Author(s):  
Sébastien Fournier ◽  
Roumiana Gulemetova ◽  
Cécile Baldy ◽  
Vincent Joseph ◽  
Richard Kinkead
Keyword(s):  
Adult Female ◽  
Maternal Separation ◽  
Respiratory Control ◽  
Female Rats ◽  
Whole Body ◽  
Hormone Regulation ◽  
Adult Rats ◽  
Ventilatory Responses ◽  
Neonatal Stress ◽  
The Impact

Human and animal studies on sleep-disordered breathing and respiratory regulation show that the effects of sex hormones are heterogeneous. Because neonatal stress results in sex-specific disruption of the respiratory control in adult rats, we postulate that it might affect respiratory control modulation induced by ovarian steroids in female rats. The hypoxic ventilatory response (HVR) of adult female rats exposed to neonatal maternal separation (NMS) is ∼30% smaller than controls (24), but consequences of NMS on respiratory control in aging female rats are unknown. To address this issue, whole body plethysmography was used to evaluate the impact of NMS on the HVR (12% O2, 20 min) of middle-aged (MA; ∼57 wk old) female rats. Pups subjected to NMS were placed in an incubator 3 h/day for 10 consecutive days (P3 to P12). Controls were undisturbed. To determine whether the effects were related to sexual hormone decline or aging per se, experiments were repeated on bilaterally ovariectomized (OVX) young (∼12 wk old) adult female rats. OVX and MA both reduced the HVR significantly in control rats but had little effect on the HVR of NMS females. OVX (but not aging) reduced the anapyrexic response in both control and NMS animals. These results show that hormonal decline decreases the HVR of control animals, while leaving that of NMS female animals unaffected. This suggests that neonatal stress alters the interaction between sex hormone regulation and the development of body temperature, hormonal, and ventilatory responses to hypoxia.

scholarly journals Vulnerability factors for mephedrone-induced conditioned place preference in rats—the impact of sex differences, social-conditioning and stress

2021 ◽  
Author(s):  
Olga Wronikowska ◽  
Maria Zykubek ◽  
Łukasz Kurach ◽  
Agnieszka Michalak ◽  
Anna Boguszewska-Czubara ◽  
...  
Keyword(s):  
Sex Differences ◽  
Conditioned Place Preference ◽  
Low Dose ◽  
Social Factor ◽  
Place Preference ◽  
Female Rats ◽  
Male Rats ◽  
Social Conditioning ◽  
Male And Female Rats ◽  
The Impact

Abstract Rationale Mephedrone is a frequently overused drug of abuse that belongs to the group of novel psychoactive substances. Although its mechanism of action, as well as toxic and psychoactive effects, has been widely studied, the role of different factors that could contribute to the increased vulnerability to mephedrone abuse is still poorly understood. Objectives The aim of the presented study was to assess the impact of several factors (sex differences, social-conditioning, and chronic mild unpredictable stress — CMUS) on the liability to mephedrone-induced reward in Wistar rats. Methods The rewarding effects of mephedrone in male and female rats were assessed using the conditioned place preference (CPP) procedure. Furthermore, the impact of social factor and stress was evaluated in male rats using social-CPP and CMUS-dependent CPP, respectively. Results Mephedrone induced classic-CPP in female (10 mg/kg), as well as in male (10 and 20 mg/kg) rats. However, the impact of mephedrone treatment during social-CPP was highly dose-dependent as the rewarding effects of low dose of mephedrone (5 mg/kg; non-active in classic-CPP) were potentiated when administered during social-conditioning. Interestingly, social-conditioning with a higher dose of 20 mg/kg (that induced classic-CPP) was able to reverse these effects. Finally, CMUS potentiated rewarding effects of a low dose of mephedrone (5 mg/kg) and increased the level of corticosterone in rats’ prefrontal cortex and hippocampus. Conclusions Altogether, the presented results give new insight into possible factors underlying the vulnerability to mephedrone abuse and can serve as a basis for further studies assessing mechanisms underlying observed effects.

Effects of rearing temperature on body weight and abdominal fat in male and female rats

1998 ◽  
Vol 274 (2) ◽  
pp. R398-R405 ◽  
Author(s):  
James B. Young ◽  
Yasunobu Shimano
Keyword(s):  
Weight Gain ◽  
Later Life ◽  
Female Rats ◽  
Male Rats ◽  
Fat Accumulation ◽  
Rearing Temperature ◽  
Male And Female Rats ◽  
Postnatal Environment ◽  
Temperature Exposure ◽  
The Impact

Thermoregulatory mechanisms are influenced by the temperature of the postnatal environment. Animals reared in cool environments are more tolerant of cold as adults, whereas those reared in warm conditions are more tolerant of heat. Because diet-induced and thermoregulatory thermogenesis share common features, studies examined the impact of rearing temperature on weight gain and fat accumulation. Rats reared at 18°C gained more weight and accumulated more fat in abdominal depots than animals reared at 30°C when both were housed at a common temperature, responses that were exacerbated by ad libitum access to sucrose. Male rats reared at 30°C were less affected by sucrose than 18°C-reared males, whereas female rats reared at 18 or 30°C were similarly susceptible. During exposure to 18°C, fat accumulation in abdominal depots increased in males but decreased in females. These data suggest that early temperature exposure influences weight gain and fat accumulation in later life, a difference that is most apparent when animals are housed at a common temperature.

scholarly journals High-fat diet-induced hypertension is associated with a proinflammatory T cell profile in male and female Dahl salt-sensitive rats

2018 ◽  
Vol 315 (6) ◽  
pp. H1713-H1723 ◽  
Author(s):  
Lia E. Taylor ◽  
Ellen E. Gillis ◽  
Jacqueline B. Musall ◽  
Babak Baban ◽  
Jennifer C. Sullivan
Keyword(s):  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
High Fat Diet ◽  
Female Rats ◽  
Male Rats ◽  
High Fat ◽  
Male And Female ◽  
The Impact ◽  
Cell Profile

Evidence supports a sex difference in the impact of a high-fat diet (HFD) on cardiovascular outcomes, with male experimental animals exhibiting greater increases in blood pressure (BP) than female experimental animals. The immune system has been implicated in HFD-induced increases in BP, and there is a sex difference in T-cell activation in hypertension. The goal of this study was to determine the impact of HFD on BP and aortic and renal T cell profiles in male and female Dahl salt-sensitive (DSS) rats. We hypothesized that male DSS rats would have greater increases in BP and T cell infiltration in response to a HFD compared with female DSS rats. BP was measured by tail-cuff plethysmography, and aortic and renal T cells were assessed by flow cytometric analysis in male and female DSS rats on a normal-fat diet (NFD) or HFD from 12 to 16 wk of age. Four weeks of HFD increased BP in male and female DSS rats to a similar degree. Increases in BP were accompanied by increased percentages of CD4+ T cells and T helper (Th)17 cells in both sexes, although male rats had more proinflammatory T cells. Percentages of renal CD3+ and CD4+ T cells as well as Th17 cells were increased in both sexes by the HFD, although the increase in CD3+ T cells was greater in male rats. HFD also decreased the percentage of aortic and renal regulatory T cells in both sexes, although female rats maintained more regulatory T cells than male rats regardless of diet. In conclusion, both male and female DSS rats exhibit BP sensitivity to a HFD; however, the mechanisms mediating HFD-induced increases in BP may be distinct as male rats exhibit greater increases in the percentage of proinflammatory T cells than female rats. NEW & NOTEWORTHY Our study demonstrates that male and female Dahl salt-sensitive rats exhibit similar increases in blood pressure to a high-fat diet and an increase in aortic and renal T cells. These results are in contrast to studies showing that female rats remain normotensive and/or upregulate regulatory T cells in response to hypertensive stimuli compared with male rats. Our data suggest that a 4-wk high-fat diet has sex-specific effects on the T cell profile in Dahl salt-sensitive rats.

scholarly journals Inflammation-Susceptible Lewis Rats Show Less Sensitivity Than Resistant Fischer Rats in the Formalin Inflammatory Pain Test and With Repeated Thermal Testing

2006 ◽  
Vol 95 (5) ◽  
pp. 2889-2897 ◽  
Author(s):  
William R. Lariviere ◽  
M. Abdus Sattar ◽  
Ronald Melzack
Keyword(s):  
Maternal Separation ◽  
Differential Susceptibility ◽  
Inbred Strains ◽  
Female Rats ◽  
Male Rats ◽  
Thermal Testing ◽  
Baseline Sensitivity ◽  
Lewis Rats ◽  
Thermal Nociception ◽  
Fischer Rats

Comparisons between Lewis and Fischer inbred strains of rats are used frequently to study the effect of inherent differences in function of the hypothalamic-pituitary-adrenal axis on pain-relevant traits, including differential susceptibility to chronic inflammatory disease and differential responsiveness to analgesic drugs. Increasing use of genetic models including transgenic knockout mice and inbred strains of rodents has raised our awareness of, and the importance of, thorough characterization (or phenotyping) of the strains of rodents being compared. Furthermore, genetic variability in analgesic sensitivity is correlated with, and may be caused by, genetically determined baseline sensitivity. Thus in this study, baseline inflammatory and thermal nociceptive sensitivities were measured in awake male and female Lewis and Fischer rats to examine whether the results could explain relevant strain differences reported in the literature. The effect of maternal separation was also examined and no effect was found on nociceptive sensitivity, corticosterone responses, or the development of adjuvant-induced arthritis, a model of rheumatoid arthritis. Lewis rats and female rats were more sensitive to thermal nociception in the tail withdrawal test (mean of 3 trials) than Fischer rats and male rats, respectively. Unexpectedly, the more inflammation-susceptible Lewis rats were less sensitive in the formalin inflammatory nociception test, and showed a significant decrease in sensitivity with repeated thermal nociceptive testing, whereas Fischer rats did not. These results affect the interpretation of previously observed results. Further study of the underlying mechanisms and the relevance to differential susceptibility to chronic inflammation is warranted.

Change from beta- to alpha-adrenergic glycogenolysis induced by corticosteroids in female rat liver

1997 ◽  
Vol 273 (1) ◽  
pp. R153-R160
Author(s):  
M. Moriyama ◽  
Y. Nakanishi ◽  
S. Tsuyama ◽  
Y. Kannan ◽  
M. Ohta ◽  
...  
Keyword(s):  
Glucose Production ◽  
Plasma Corticosterone ◽  
Mature Female ◽  
Female Rats ◽  
Male Rats ◽  
Female Rat ◽  
Circadian Variations ◽  
Male And Female ◽  
Male And Female Rats ◽  
The Difference

The conversion of beta- to alpha-adrenergic glycogenolysis by corticosteroids was studied in perfused livers of mature female rats. Isoproterenol stimulated glucose production more effectively in female rats than in male rats, but the difference in its stimulatory effect disappeared in adrenalectomized (ADX) rats, whereas it remained in adrenodemedulated rats. When ADX female rats were treated with dexamethasone sulfate, alpha-responses increased and beta-responses decreased, depending on the concentration of dexamethasone sulfate. The treatment of female rats with 1.5 mg/kg dexamethasone sulfate changed the levels of the alpha- and beta-responses to those observed in male rats, and the changes were associated with changes in the number of receptors. Although periodicity of changes in plasma corticosterone levels was observed in both male and female rats, the extent of circadian variations was significantly lower in female rats during the estrous cycle than in male rats. The variations in plasma corticosterone levels and in both alpha- and beta-responses after ovariectomy approached those in male rats. The results suggest that the level of plasma corticosterone might play an important role in the regulation of the relative levels of alpha- and beta-adrenergic responses in female rats.

scholarly journals Gender Difference in Renal Blood Flow Response to Angiotensin II Administration after Ischemia/Reperfusion in Rats: The Role of AT2 Receptor

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Maryam Maleki ◽  
Mehdi Nematbakhsh
Keyword(s):  
Blood Flow ◽  
Angiotensin Ii ◽  
Renal Blood Flow ◽  
Ischemia Reperfusion ◽  
Renal Ischemia ◽  
Female Rats ◽  
Male Rats ◽  
Ang Ii ◽  
The Impact

Background. Renal ischemia/reperfusion (I/R) is one of the major causes of kidney failure, and it may interact with renin angiotensin system while angiotensin II (Ang II) type 2 receptor (AT2R) expression is gender dependent. We examined the role of AT2R blockade on vascular response to Ang II after I/R in rats.Methods.Male and female rats were subjected to 30 min renal ischemia followed by reperfusion. Two groups of rats received either vehicle or AT2R antagonist, PD123319. Mean arterial pressure (MAP), and renal blood flow (RBF) responses were assessed during graded Ang II (100, 300, and 1000 ng/kg/min, i.v.) infusion at controlled renal perfusion pressure (RPP).Results.Vehicle or antagonist did not alter MAP, RPP, and RBF levels significantly; however, 30 min after reperfusion, RBF decreased insignificantly in female treated with PD123319 (P=0.07). Ang II reduced RBF and increased renal vascular resistance (RVR) in a dose-related fashion (Pdose<0.0001), and PD123319 intensified the reduction of RBF response in female (Pgroup<0.005), but not in male rats.Conclusion.The impact of the AT2R on vascular responses to Ang II in renal I/R injury appears to be sexually dimorphic. PD123319 infusion promotes these hemodynamic responses in female more than in male rats.

Inhalation Toxicity and Genotoxicity of Hydrofluorocarbon (HFC)-236fa and HFC-236ea

2000 ◽  
Vol 19 (2) ◽  
pp. 69-83 ◽  
Author(s):  
William J. Brock ◽  
David P. Kelly ◽  
Susan M. Munley ◽  
Karin S. Bentley ◽  
Kathy M. McGown ◽  
...  
Keyword(s):  
Developmental Toxicity ◽  
Human Lymphocytes ◽  
Female Rats ◽  
Male Rats ◽  
Whole Body ◽  
Seminiferous Tubules ◽  
Inhalation Toxicity ◽  
Male And Female ◽  
Male And Female Rats

The acute, subchronic, and developmental and genetic toxicity of hydrofluorocarbon (HFC)-236fa and HFC-236ea were evaluated to assist in establishing proper handling guidance. In acute inhalation studies, rats were exposed whole body for 4 hours to various concentrations of each isomer. Based on the lack of mortality, the approximate lethal concentration for HFC-236ea for male rats was > 85,000 ppm. For HFC-236fa, the LC50 for males and females (combined) was > 457,000 ppm. Narcotic-like effects, e.g., prostration, incoordination, and reduced motor activity, were observed only during exposure to either isomer, but were not evident after termination of exposure. In cardiac sensitization studies, HFC-236ea induced cardiac sensitization at ≥ 35,000 ppm, with fatal responses occurring at 50,000 ppm and greater. For HFC-236fa, a cardiac sensitization response was observed at 150,000 ppm and greater but not at 100,000 ppm. A fatal cardiac sensitization response was observed in one dog exposed to 150,000 ppm HFC-236fa. In 90-day subchronic inhalation studies, male and female rats were exposed whole body to HFC-236ea at concentrations of 0, 5000, 20,000, or 50,000 ppm for 6 hours/day, 5 days/week. Similarly, male and female rats were exposed whole body to HFC-236fa at concentrations of 0, 5000, 20,000, or 50,000 ppm for 6 hours/day, 5 days/week. During exposure, narcotic-like effect (reduced acoustic startle response) was observed at 50,000 ppm with both isomers, although there appeared to be an adaptive response to this effect as the study progressed. With HFC-236ea, dilatation of the seminiferous tubules, without effects on germ or Sertoli cells, was observed only in rats at 50,000 ppm. No other effects on in-life measures or on clinical or anatomic pathology, including histopathology, were observed for either isomer. In rat developmental toxicity studies, no evidence of embryotoxicity or teratogenicity was observed with either isomer exposed up to 50,000 ppm during gestational days 7 to 16. Also, no developmental toxicity was observed in rabbits exposed to HFC-236fa at concentrations of up to 50,000 ppm during gestational days 7 to 19. Neither of the HFC-236 isomers was mutagenic in the Ames reverse mutation assay or clastogenic in the chromosomal aberration assay with human lymphocytes. No increase in chromosomal aberrations was observed in in vivo micronucleus studies with either isomer.

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