Search results for "Corticosterone"
showing 10 items of 72 documents
Competition for resources modulates cell-mediated immunity and stress hormone level in nestling collared doves (Streptopelia decaocto)
2008
International audience; Competitive stress imposed by hatching asynchrony may affect developmental trajectories of offsprings by regulating resource allocation between growth and other fitness-related traits. For instance, the down-regulation of immunity is a commonly observed phenomenon under stressful conditions. However, physiological mechanisms that regulate resources allocation to growth and immune functions in response to competition for resources, as well as inter-sexual differences in physiological strategies, are still poorly investigated. To partially fill this gap, we first conducted a descriptive study on chicks of the collared dove (Streptopelia decaocto), a species producing t…
Forest management is associated with physiological stress in an old–growth forest passerine
2003
We investigated how physiological stress in an area-sensitive old-growth forest passerine, the Eurasian treecreeper (Certhia familiaris), is associated with forest fragmentation and forest structure. We found evidence that the concentrations of plasma corticosterone in chicks were higher under poor food supply in dense, young forests than in sparse, old forests. In addition, nestlings in large forest patches had lower corticosterone levels and a better body condition than in small forest patches. In general, corticosterone levels were negatively related to body condition and survival. We also found a decrease in corticosterone levels within the breeding season, which may have been a result …
The effects of glucocorticoids on thymidine kinase and nucleoside phosphotransferase during development of chicken embryo retina.
1983
AbstractThymidine kinase in chick embryo retina reaches its highest values on the 8–10th day of development, then declines reaching the lowest value at hatching. The rate of DNA synthesis essentially follows this activity while, in contrast, nucleoside phosphotransferase increases progressively during development. Glucocorticoids at 5 × 10−6M lower the level of thymidine kinase in isolated retinas of chick embryo. The most effective steroid was hydrocortisone. The effect was observed in retinas from 8–18-day-old chick embryo and, except on the 18th day, was always of the same magnitude. We suggest that a glucocorticoid can be the natural factor responsible for the marked fall in thymidine k…
Effects of acute social stress on the conditioned place preference induced by MDMA in adolescent and adult mice
2014
Exposure to social defeat stress increases the rewarding effects of psychostimulants in animal models, but its effect on 3,4-methylenedioxymethylamphetamine (MDMA) reward has received little attention. In the present study, we evaluated the influence of social defeat on the rewarding effects of MDMA in adolescent [postnatal day (PND) 29-40] and adult (PND 50-61) male mice using the conditioned place preference paradigm. Experimental mice were exposed to social defeat in an agonistic encounter before each session of conditioning with 1.25 or 10 mg/kg of MDMA. The effects of social defeat on corticosterone levels and the motor or the anxiogenic effects of MDMA were also evaluated. Mice expose…
Rewarding effects of 3,4-methylenedioxymethamphetamine (“Ecstasy”) in dominant and subordinate OF-1 mice in the place preference conditioning paradigm
2006
We tested the ability of 3,4-methylenedioxymethamphetamine (MDMA) to induce conditioned place preference (CPP) in dominant and subordinate OF-1 mice subjected to cohabitation and repeated sessions of agonistic confrontation, as well as in non-confronted mice. We selected doses of MDMA (2, 6, 10 mg/kg) previously reported to induce CPP in mice and we measured expression of c-Fos evoked by the treatments in non-confronted mice. MDMA induced c-Fos protein in several corticolimbic regions involved in drug-induced reward. Mice were exposed to brief sessions of agonistic confrontation on 5 consecutive days. Determinations of circulating hormones and drug conditioning tests were carried out on com…
Cognitive and behavioural effects induced by social stress plus MDMA administration in mice
2017
Adverse life experiences such as social stress may make an individual more vulnerable to drug addiction and mental disorders associated with drug consumption. The present work aimed to evaluate the effects of stress induced by acute social defeat combined with the administration of 3,4-methylenedioxymethamphetamine (MDMA) on depression-like behaviour, memory function and motor response to drug in late adolescent male mice. Two groups of mice were exposed to social defeat (SD) during four encounters with an aggressive co-specific, which took place on alternate days. Immediately after defeat, animals were treated with saline or MDMA 10mg/kg (SD+SAL and SD+MDMA). In control groups, mice were p…
Neuroendocrine responses in neonatal mother-deprived rabbits.
2009
To study both short- and long-term adaptation mechanisms activated by rabbits which were separated from their mothers (DLS) for 48 h between postnatal days 9 and 11, we examined plasma corticosterone concentrations before, during, and after DLS as well as the expression of glucocorticoid receptor (GR) in the hippocampus and the adrenal axis responses to a mild stress stimuli or exogenous ACTH injection. At postnatal day 10, plasma corticosterone concentration of DLS rabbits was similar to that of controls, but rose two-fold at day 11 (17.7 + or - 1.3 vs. 9.3 + or - 1.2 microg/dl, P0.01) and then decreased at day 12, when suckling was allowed again, to match those of controls with no differe…
Synthesis and gas chromatographic-mass spectrometric analysis of reduced compounds derived from 6 alpha- and 6 beta-hydroxy-11-deoxycorticosterone.
1989
Abstract A series of thirty two 6-hydroxylated steroids were synthesized by selective reduction of the 4–5 double bond, the 3-oxo group, and/or the 20-oxo group of 6α- and 6β-hydroxyDOC. The different reactions leading to the production of specific isomers are discussed. The gas chromatographic and spectrometric characteristics of the methoxime-trimethylsilyl (MO-TMS) or trimethylsilyl (TMS) derivatives of the isomers obtained are given. The gas chromatographic separation of the syn- and anti -isomers of the methoxime in position 3 was found to be characteristic of the configuration of the hydroxyl in position 6. The difference between methylene unit values of syn- and anti- isomers is much…
Chronic non-invasive glucocorticoid administration decreases polysialylated neural cell adhesion molecule expression in the adult rat dentate gyrus
2004
The expression of the polysialylated neural cell adhesion molecule (PSA-NCAM) is increased in the hippocampus after chronic restraint stress (CRS) and may play a permissive role in structural changes that include dendrite reorganization in dentate gyrus (DG) and CA3 pyramidal neurons and suppression of neurogenesis in DG. We report that chronic oral corticosterone (CORT) administration decreases the number of PSA-NCAM immunoreactive granule neurons in the adult rat dentate gyrus, and the available evidence suggests that this is an indirect effect of CORT, possibly involving excitatory amino acids, that may not be directly related to neurogenesis. Because CORT treatment reduces but does not …
Behavioural Consequences of P-Glycoprotein Deficiency in Mice, with Special Focus on Stress-Related Mechanisms
2012
P-glycoprotein (P-gp), an efflux transporter localised in the blood-brain barrier, limits the access of multiple xenobiotics to the central nervous system. Whether it is also implemented in the transport of the endogenous glucocorticoid corticosterone is a matter of debate. The P-gp knockout mouse model [abcb1a/b (-/-)] has been shown to differ in the functioning of the hypothalamic-pituitary adrenal (HPA) axis. In the present study, we investigated the behaviour of abcb1a/b (-/-) and wild-type mice with respect to stress-related tests and the effects of corticosterone. Behavioural activities were assessed in the open field (OF) test for 4 days, and in the forced swimming test (FST) and tai…