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Query: UNIPROT:P01189 (
beta-endorphin
)
21,003
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
We investigated the effects of perinatal maternal malnutrition on the hypothalamo-pituitary-adrenal (HPA) axis activity in both basal and stressful conditions in newborn rats at weaning. Mothers from the control group were fed ad libitum. Mothers exposed to food restriction received 50% (FR50) of the daily intake of pregnant dams during the last week of gestation (Pre group), lactation (Post group) or both periods (PP group) in order to compare the long-term effects of gestational and/or lactational restriction. FR50 reduced the body growth of pups from the Post and PP groups as soon as day 11 until day 21 after birth. At weaning, pups of the Post and PP groups showed reduced adrenal, thymus and liver weights. Although the plasma
adrenocorticotropic hormone (ACTH)
level was reduced in pups, FR50 affected neither
corticotropin
-releasing hormone expression and peptide synthesis in the hypothalamus nor proopiomelanocortin expression in the adenohypophysis. Basal circulating levels of corticosterone were not markedly affected by FR50, but free corticosterone concentration was increased in the PP group. Plasma corticosterone-binding globulin (CBG) was decreased in newborns from both the Post and PP groups. Mineralocorticoid receptor gene expression was significantly increased in both
CA1
and CA3 hippocampal areas in the PP group. Glucocorticoid receptor gene expression was increased in
CA1
, CA2 and dentate gyrus hippocampal areas in the Pre group, as well as in
CA1
, CA3 and DG areas in the Post group. The ether inhalation-induced plasma ACTH increase was weaker in pups from the Post and PP groups. Similarly, the ether inhalation-induced plasma corticosterone increase returned to basal levels in the Post group, or to weaker values than baseline in the PP group 90 min after this stressful procedure. The present work suggests that maternal food restriction during the perinatal period (gestation and lactation) or during lactation only reduces the postnatal somatic growth of pups and disturbs the activity of the HPA axis at weaning under both resting and stress conditions. A reduction in the plasma CBG-binding capacity, associated with a probable increase in hippocampal corticosteroid receptors, could reinforce glucocorticoid-mediated negative feedback and shorten stress-induced activation of the HPA axis in pups at weaning.
...
PMID:Perinatal maternal food restriction induces alterations in hypothalamo-pituitary-adrenal axis activity and in plasma corticosterone-binding globulin capacity of weaning rat pups. 1181 34
Using the in situ hybridization, a distribution of
corticotropin
-releasing hormone (CRH) receptors CRH-1 and CRH-2 in the rat brain has been studied. Brain levels of CRH-1 mRNA were higher than the those of CRH-2 mRNA. Most intensive CRH-1 gene expression was observed in the forebrain, including neocortex, archicortex, paleocortex and cerebellar cortex. In addition, significant CRH-1 mRNA expression was detected in the red nucleus, pontine nucleus, cochlear nucleus and reticular tegmental nucleus. CRH-2 mRNA was intensively expressed in the olfactory structures, corticomedial amygdala,
CA1
-CA4 of hippocampus, ventramedial hypothalamus and several modullar nuclei. Moderate CRH-2 mRNA level were seen in the dorsomedial neostriatum. The findings indicate that within the brain two types of CRH receptors are widely expressed. A distinct pattern of CRH-1 and CRH-2 expression in the brain appears to underline the functional specifics of the CRH actions in brain structures.
...
PMID:[Localization of corticoliberin receptors in the rat brain]. 1184 Sep 63
In humans, an altered control of cortisol secretion was reported in adult men born with a low birth weight making the hypothalamic-pituitary-adrenal (HPA) axis a possible primary target of early life programming. In rats, we have recently shown that maternal food restriction during late pregnancy induces both an intrauterine growth retardation and an overexposure of fetuses to maternal corticosterone, which disturb the development of the HPA axis in offspring. The first aim of this work was to investigate, in adult male rats, whether perinatal malnutrition has long-lasting effects on the HPA axis activity during both basal and stressful conditions. Moreover, as the HPA axis and sympathetic nervous system are both activated by stress, the second aim of this work was to investigate, in these rats, the adrenomedullary catecholaminergic system under basal and stressful conditions. This study was conducted on 4-month-old male rats malnourished during their perinatal life and on age-matched control animals. Under basal conditions, perinatal malnutrition reduced body weight and plasma corticosteroid-binding globulin (CBG) level but increased mineralocorticoid receptor (MR) gene expression in
CA1
hippocampal area. After 30 min of restraint, perinatally malnourished (PM) rats showed increased plasma noradrenaline,
adrenocorticotropin
hormone (ACTH) and corticosterone concentrations similarly as controls, but calculated plasma-free corticosterone concentration was significantly higher and adrenaline level lower than controls. During the phase of recovery, PM rats showed a rapid return of plasma ACTH and corticosterone concentrations to baseline levels in comparison with controls. These data suggest that in PM rats, an elevation of basal concentrations of corticosterone, in face of reduced CBG and probably increased hippocampal MR lead to a much larger impact of corticosterone on target cells that mediate the negative-feedback mechanism on the activities of both the HPA axis and sympathoadrenal one.
...
PMID:Perinatal malnutrition programs sympathoadrenal and hypothalamic-pituitary-adrenal axis responsiveness to restraint stress in adult male rats. 1184 73
In addition to regulating the neuroendocrine stress response,
corticotropin
-releasing hormone (CRH) has been implicated in both normal and pathological behavioral and cognitive responses to stress. CRH-expressing cells and their target neurons possessing CRH receptors (CRF1 and CRF2) are distributed throughout the limbic system, but little is known about the regulation of limbic CRH receptor function and expression, including regulation by the peptide itself. Because CRH is released from limbic neuronal terminals during stress, this regulation might play a crucial role in the mechanisms by which stress contributes to human neuropsychiatric conditions such as depression or posttraumatic stress disorder. Therefore, these studies tested the hypothesis that CRH binding to CRF1 influenced the levels and mRNA expression of this receptor in stress-associated limbic regions of immature rat. Binding capacities and mRNA levels of both CRF1 and CRF2 were determined at several time points after central CRH administration. CRH downregulated CRF1 binding in frontal cortex significantly by 4 h. This transient reduction (no longer evident at 8 h) was associated with rapid increase of CRF1 mRNA expression, persisting for >8 h. Enhanced CRF1 expression-with a different time course-occurred also in hippocampal CA3, but not in
CA1
or amygdala, CRF2 binding and mRNA levels were not altered by CRH administration. To address the mechanisms by which CRH regulated CRF1, the specific contributions of ligand-receptor interactions and of the CRH-induced neuronal stimulation were examined. Neuronal excitation without occupation of CRF1 induced by kainic acid, resulted in no change of CRF1 binding capacity, and in modest induction of CRF1 mRNA expression. Furthermore, blocking the neuroexcitant effects of CRH (using pentobarbital) abolished the alterations in CRF1 binding and expression. These results indicate that CRF1 regulation involves both occupancy of this receptor by its ligand, as well as "downstream" cellular activation and suggest that stress-induced perturbation of CRH-CRF1 signaling may contribute to abnormal neuronal communication after some stressful situations.
...
PMID:Corticotropin-releasing hormone (CRH) downregulates the function of its receptor (CRF1) and induces CRF1 expression in hippocampal and cortical regions of the immature rat brain. 1209 84
Dehydration, a classic homeostatic stressor in rats, leads to a series of well characterized endocrine responses including stimulation of the hypothalamo-pituitary-adrenal (HPA) axis. In this study, the hypothesis to be tested was that a 50% maternal food restriction (FR50) in late gestation and lactation may have long-term repercussions on HPA axis responsiveness to dehydration in offspring. For this purpose, we studied HPA axis activity in 4-month-old control (C) and perinatally malnourished male rats after a 72-hour water deprivation period. Furthermore, we investigated the long-lasting effects of perinatal maternal malnutrition on the basal activity of the HPA axis. Under basal conditions, rats exposed to perinatal malnutrition showed reduced body weight, enhanced mineralocorticoid receptor (MR) mRNA levels in CA2 and CA3 hippocampal areas, but decreased glucocorticoid receptor (GR) mRNA levels in
CA1
, CA3 and dentate gyrus (DG) areas. In contrast, the levels of
corticotropin
-releasing hormone (CRH) and vasopressin (VP) mRNAs in the hypothalamic paraventricular nucleus (PVN) as well as of VP mRNA in the supraoptic nucleus (SON) were unaffected by maternal undernutrition. Expression of proopiomelanocortin (POMC) in the adenohypophysis was significantly enhanced, whereas prohormone convertase-1 (PC1) was not affected. Perinatal malnutrition reduced absolute adrenal weight but did not affect circulating levels of
adrenocorticotropin
(ACTH), corticosterone and free corticosterone as well as corticosteroid-binding globulin (CBG) binding capacity. Seventy-two hours of dehydration induced a decrease in body weight and CRH mRNA levels in PVN of controls as well as of FR50 rats, but also led to a rise in plasma corticosterone and free corticosterone without changing CBG binding capacity. Dehydration also induced an increase in adenopituitary POMC (C) and PC1 (FR50), PVN and SON VP (C) and GR in
CA1
hippocampal area (FR50) mRNA levels and plasma ACTH (C), but a decrease in MR in DG (C) and GR in CA3 and DG (C) mRNA levels. We conclude that maternal food restriction during the perinatal period affects (1) the adult basal activity of the HPA axis with mainly opposite effects on hippocampal MR and GR gene expression and an increase in adenopituitary POMC gene expression, and (2) the responsiveness to water deprivation in adults. In the latter case, the rise in plasma ACTH levels, adenopituitary POMC gene expression, hypothalamic VP gene expression, and the decrease in hippocampal MR gene expression in DG and GR gene expression in CA3 and DG observed in controls are lacking in FR50 rats. In contrast, drastic adenopituitary PC1 gene expression occurred in FR50 rats but not in control animals.
...
PMID:Altered control of the hypothalamo-pituitary-adrenal axis in adult male rats exposed perinatally to food deprivation and/or dehydration. 1241 41
The central fragment of cholecystokinin, CCK8, plays a critical role in stress-related changes in behavior and memory. Therefore, we investigated whether the endogenous cholecystokininergic system is involved in the impairment of attention and/or memory induced by stressful conditions. Plasma corticosterone concentrations increased three-fold and plasma
adrenocorticotropin
(ACTH); concentrations increased five-fold when rats were maintained in the open arm of an elevated plus maze for 5 min. The same stress conditions impaired spatial recognition in the two-trial memory task. In addition, this stress led to a significant decrease in the extracellular levels of cholecystokinin-like immunoreactivity in the dorsal subiculum/
CA1
of the hippocampus and partially suppressed the increase obtained during the acquisition phase of memory. This suggests that the cholecystokininergic system in the hippocampus is involved in stress-induced impairment of spatial recognition memory.
...
PMID:Involvement of brain endogenous cholecystokinin in stress-induced impairment of spatial recognition memory. 1267 33
Housing rats in an enriched environment improves functional outcome after ischemic stroke, this may reflect neuronal plasticity in brain regions outside the lesion. Which components of the enriched environment that are of greatest importance for recovery after brain ischemia is uncertain. We have previously found that enriched environment and social interaction alone both improve functional recovery after focal cerebral ischemia, compared with isolated housing with voluntary wheel-running. In this study, the aim was to separate components of the enriched environment and investigate the effects on some potential mediators of improved functional recovery; such as the inducible transcription factors nerve growth factor-induced gene A (NGFI-A) and NGFI-B, and the glucocorticoid and serotonin systems. After permanent middle cerebral artery occlusion, rats were divided into four groups: individually housed with no equipment (deprived group), individually housed with free access to a running wheel (running group), housed together in a large cage with no equipment (social group) or in a large cage furnished with exchangeable bars, chains and other objects (enriched group). mRNA expression of inducible transcription factors, serotonin and glucocorticoid receptors was determined with in situ hybridisation 1 month after cerebral ischemia. Rats housed in enriched or social environments showed significantly higher mRNA expression of NGFI-A and NGFI-B in cortical regions outside the lesion and in the
CA1
(cornu ammonis region of the hippocampus), compared with isolated rats with or without a running wheel. NGFI-A and NGFI-B mRNA expression in cortex and in
CA1
was significantly correlated to functional outcome. 5-Hydroxytryptamine receptor 1A (5-HT(1A)) mRNA expression and binding, as well as 5-HT(2A) receptor mRNA expression were decreased in the hippocampus (CA4 region) of the running wheel rats. Mineralocorticoid receptor gene expression was increased in the dentate gyrus amongst wheel-running rats. No group differences were found in plasma corticosterone levels or mRNA levels of glucocorticoid receptor,
corticotropin
-releasing hormone, 5-HT(2C) or c-fos. In conclusion, we have found that social interaction is a major component of the enriched environment regarding the effects on NGFI-A and NGFI-B expression. These transcription factors may be important mediators of improved functional recovery after brain infarctions, induced by environmental enrichment.
...
PMID:Effects of postischemic environment on transcription factor and serotonin receptor expression after permanent focal cortical ischemia in rats. 1280 85
To assess the interaction between stress and energy homeostasis, we immobilized male Sprague-Dawley rats prone to diet-induced obesity (DIO) or diet resistance (DR) once for 20 min and then fed them either low-fat (4.5%) chow or a medium-fat (31%), high-energy (HE) diet for 9 days. Stressed, chow-fed DIO rats gained less, while stressed DIO rats on HE diet gained more body weight and had higher feed efficiency and plasma leptin levels than unstressed controls. Neither stress nor diet affected DR body weight gain. While stress-induced plasma corticosterone levels did not differ between phenotypes, DIO rats were initially more active in an open field and had higher hippocampal dentate gyrus and
CA1
glucocorticoid receptor (GR) mRNA than DR rats, regardless of prior stress or diet. HE diet intake was associated with raised dentate gyrus and
CA1
GR and amygdalar central nucleus (CeA)
corticotropin
-releasing hormone (CRH) mRNA expression, while stress was associated with reduced hypothalamic dorsomedial nucleus Ob-R mRNA and CeA CRH specifically in DIO rats fed HE diet. Thus a single stress triggers a complex interaction among weight gain phenotype, diet, and stress responsivity, which determines the body weight and adiposity of a given individual.
...
PMID:Stress facilitates body weight gain in genetically predisposed rats on medium-fat diet. 1281 43
Alterations in the opioid system in the hippocampal formation and some of the possible functional consequences were investigated in adult male rats that were prenatally exposed to either saline or morphine (10 mg/kg twice daily on gestational days 11-18). In situ hybridization and Northern blots were used to measure proenkephalin and prodynorphin mRNA, and radioimmunoassays quantified proenkephalin- and prodynorphin-derived peptide levels in the dentate gyrus, CA3, and
CA1
subfields of the hippocampal formation. Prenatal morphine exposure in male rats decreases proenkephalin and increases prodynorphin mRNA selectively in the granule cell layer of the dentate gyrus. Similarly,
met-enkephalin
peptide levels are decreased and dynorphin B peptide levels are increased in the dentate gyrus but not CA3 or
CA1
of prenatally morphine-exposed males. In addition, there are decreases in dynorphin-derived peptides in the CA3 subfield. Receptor autoradiography revealed increases in the density of micro but not delta receptor labeling in discrete strata of specific hippocampal subfields in morphine-exposed males. Because alterations in the hippocampal opioid system suggest possible alterations in the excitability of the hippocampal formation, changes in opioid regulation of seizures were examined. Morphine exposure, however, does not alter the latency to onset or number of episodes of wet dog shakes or clonic seizures induced by infusion of 10 nmol [D-Ala2, MePhe4, Gly-ol5]enkephalin into the ventral hippocampal formation. Interestingly, a naloxone (5 mg/kg) injection 30 min before bicuculline administration reverses the increased latency to onset of clonic and tonic-clonic seizures in morphine-exposed males. Thus, the present study suggests that exposure of rats to morphine during early development alters the hippocampal opioid system, suggesting possible consequences for hippocampal-mediated functions.
...
PMID:Field-specific changes in hippocampal opioid mRNA, peptides, and receptors due to prenatal morphine exposure in adult male rats. 1520 53
The excitatory actions of
corticotropin
-releasing hormone (CRH) in the brain and the neuroprotective effects of CRH antagonists in models of ischemia suggest a role for this peptide in the cascade of events leading to cellular damage. The present study aimed to characterize endogenous activation of CRH in discrete brain regions following global ischemia. Time-dependent changes in CRH concentrations were assessed in 10 brain regions including hippocampal, parahippocampal, and hypothalamic regions as well as the amygdala and the frontal cortex at three post-ischemic intervals: 4, 24, and 72 h (Experiment 1). The impact of pretreatment with a neuroprotective dose of the NMDA antagonist (5R,10S)-(+)-5-Methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine hydrogen maleate (MK-801; hydrogen maleate) on 24-h ischemia-induced CRH concentrations in the 10 brain regions was also determined (Experiment 2). In vivo microdialysis was used to assess dynamic fluctuations in CRH release at the dorsal hippocampus (
CA1
pyramidal layer) and central nucleus of the amygdala (CeA; Experiment 3). Our findings revealed a rapid elevation of CRH concentrations at the piriform cortex (Pir) and hypothalamic nuclei following global ischemia. This was followed by decreased CRH concentrations at the amygdala, the frontal cortex (FC), the CA3, and the hypothalamus 24-h post-ischemia. MK-801 reversed the decreases in the hypothalamic nuclei but not in the other brain regions. Seventy-two hours post-ischemia, CRH levels returned to control values in all regions except the dentate gyrus (DG) where elevated CRH levels were observed. In vivo, a significant increase in CRH release in response to global ischemia was found at the CeA with no alterations at the
CA1
. These findings support brain region-specific ischemia-induced CRH alterations and suggest that CRH actions to mediate neuronal damage at the hippocampal
CA1
layer may be indirect.
...
PMID:Time-dependent changes in CRH concentrations and release in discrete brain regions following global ischemia: effects of MK-801 pretreatment. 1523 51
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