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.

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.

Effects of Early Maternal Separation on Biobehavioral and Neuropathological Markers of Alzheimer's Disease in Adult Male Rats

2013 ◽  
Vol 10 (4) ◽  
pp. 420-432 ◽  
Author(s):  
Eva Martisova ◽  
Barbara Aisa ◽  
Gorka Guerenu ◽  
Maria Javier Ramirez
Keyword(s):  
Adult Male ◽  
Maternal Separation ◽  
Male Rats

scholarly journals Inflammatory Pain and Corticosterone Response in Infant Rats: Effect of 5-HT1A Agonist Buspirone Prior to Gestational Stress

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Irina P. Butkevich ◽  
Viktor A. Mikhailenko ◽  
Tat'yana R. Bagaeva ◽  
Elena A. Vershinina ◽  
Anna Maria Aloisi ◽  
...  
Keyword(s):  
Hpa Axis ◽  
Inflammatory Pain ◽  
Formalin Test ◽  
Corticosterone Level ◽  
Plasma Corticosterone ◽  
Male Rats ◽  
Plasma Corticosterone Level ◽  
Infant Rats ◽  
Corticosterone Response ◽  
Gestational Stress

Our researches have shown that gestational stress causes exacerbation of inflammatory pain in the offspring; the maternal 5-HT1A agonist buspirone before the stress prevents the adverse effect. The serotonergic system and hypothalamo-pituitary-adrenal (HPA) axis are closely interrelated. However, interrelations between inflammatory pain and the HPA axis during the hyporeactive period of the latter have not been studied. The present research demonstrates that formalin-induced pain causes a gradual and prolonged increase in plasma corticosterone level in 7-day-old male rats; twenty-four hours after injection of formalin, the basal corticosterone level still exceeds the initial basal corticosterone value. Chronic treatments of rat dams with buspirone before restraint stress during gestation normalize in the offspring pain-like behavior and induce during the acute phase in the formalin test the stronger corticosterone increase as compared to the stress hormonal elevation in animals with other prenatal treatments. Negative correlation between plasma corticosterone level and the number of flexes+shakes is revealed in buspirone+stress rats. The new data enhance the idea about relativity of the HPA axis hyporeactive period and suggest that maternal buspirone prior to stress during gestation may enhance an adaptive mechanism of the inflammatory nociceptive system in the infant male offspring through activation of the HPA axis peripheral link.

Neonatal stress and attenuation of the hypercapnic ventilatory response in adult male rats: the role of carotid chemoreceptors and baroreceptors

2010 ◽  
Vol 299 (5) ◽  
pp. R1279-R1289 ◽  
Author(s):  
Frédéric S. Dumont ◽  
Richard Kinkead
Keyword(s):  
Adult Male ◽  
Maternal Separation ◽  
Ventilatory Response ◽  
Respiratory Control ◽  
Pressure Change ◽  
Male Rats ◽  
Arterial Blood ◽  
Carotid Bodies ◽  
Neonatal Maternal Separation ◽  
Underlying Mechanisms

Neonatal maternal separation (NMS) is a form of stress that disrupts respiratory control development. Awake adult male rats previously subjected to NMS show a ventilatory response to hypercapnia (HCVR; FiCO2 = 0.05) 47% lower than controls; however, the underlying mechanisms are unknown. To address this issue, we first tested the hypothesis that carotid bodies contribute to NMS-related attenuation of the HCVR by using carotid sinus nerve section or FiO2 manipulation to maintain PaO2 constant (iso-oxic) during hypercapnic hyperpnea. We then determined whether NMS-related augmentation of baroreflex sensitivity contributes to the reduced HCVR in NMS rats. Nitroprusside and phenylephrine injections were used to manipulate arterial blood pressure in both groups of rats. Pups subjected to NMS were separated from their mother 3 h/day from postnatal days 3 to 12. Control rats were undisturbed. At adulthood, rats were anesthetized [urethane (1g/kg) + isoflurane (0.5%)], and diaphragmatic electromyogram (dEMG) was measured under baseline and hypercapnic conditions (PaCO2: 10 Torr above baseline). The relative minute activity response to hypercapnia of anesthetized NMS rats was 34% lower than controls. Maintaining PaO2 constant during hypercapnia reversed this phenotype; the HCVR of NMS rats was 45% greater than controls. Although the decrease in breathing frequency during baroreflex activation was greater in NMS rats, the change observed within the range of pressure change observed during hypercapnia was minimal. We conclude that NMS-related changes in carotid body sensitivity to chemical stimuli and/or its central integration is a key mechanism in the attenuation of HCVR by NMS.

Ethosecretogram: relation of behavior to plasma corticosterone in freely moving rats

1984 ◽  
Vol 247 (1) ◽  
pp. R40-R45 ◽  
Author(s):  
I. Shiraishi ◽  
K. Honma ◽  
S. Honma ◽  
T. Hiroshige
Keyword(s):  
Locomotor Activity ◽  
Animal Behavior ◽  
Corticosterone Level ◽  
Plasma Corticosterone ◽  
Male Rats ◽  
Conscious Rats ◽  
Series Of Experiments ◽  
Freely Moving ◽  
The Right ◽  
Temporally Correlated

An ethosecretogram, which illustrates the phase relation between animal behavior and plasma hormone levels, was constructed in conscious rats. A catheter was placed into the right atrium in male rats 2 days before blood sampling. Plasma corticosterone levels were monitored individually through the catheter every 5 min over a period of several hours under freely moving conditions on an Animex, which records spontaneous locomotor activity. The results showed that the bursts of locomotor activity were temporally correlated with those of plasma corticosterone level, the peak of the former preceding the hormone peak by 15 min. Regarding the type of locomotor activity, feeding and grooming were significantly correlated with the subsequent hormone elevation, whereas drinking was not. In a separate series of experiments, effects of feeding and drinking on plasma corticosterone levels were examined in conscious rats that had been fasted or water deprived for 24 or 48 h. In both cases, feeding induced a more pronounced elevation than drinking, although locomotor activity counts per se increased more sharply in the latter. It is concluded that in the ethosecretogram specific types of locomotor activity such as feeding and grooming induce a phase-locked elevation of plasma corticosterone under freely moving conditions.

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