UNIPROT:P01189 - FACTA Search

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Query: UNIPROT:P01189 (beta-endorphin)
21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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.
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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

Clinical and preclinical studies have gathered substantial evidence that stress response alterations play a major role in the development of major depression, panic disorder, and post-traumatic stress disorder. The stress response, the hypothalamic pituitary adrenocortical (HPA) system and its modulation by corticotropin-releasing hormones (CRH),corticosteroids,and their receptors, and the roles of natriuretic peptides and neuroactive steroids are described. We review the role of the HPA system in major depression, panic disorder, and post-traumatic stress disorder and its possible relevance for treatment. Impaired glucocorticoid receptor function in major depression is associated with an excessive release of neurohormones such as CRH, to which a number of signs and symptoms characteristic of depression can be ascribed. In panic disorder, a role of central CRH in panic attacks has been suggested. Atrial natriuretic peptide (ANP) is causally involved in sodium lactate-induced panic attacks. Furthermore, preclinical and clinical data on its anxiolytic activity suggest that nonpeptidergic ANP receptor ligands may be potentially useful in the treatment of anxiety disorders. Post-traumatic stress disorder is characterized by a peripheral hyporesponsive HPA system and elevated CRH concentrations in the CSF. This dissociation is probably related to an increased risk of this disorder. We further review recent data that describe an important role of GABA(A)-receptor modulatory,3 alpha-reduced neuroactive steroids in major depression, anxiety, and its treatment. Antidepressants are effective in both depression and anxiety disorders and have major effects on the HPA system,especially on glucocorticoid and mineralocorticoid receptors. Normalization of HPA system abnormalities is a strong predictor of the clinical course, at least in major depression and panic disorder. Currently,CRH-R1 or glucocorticoid receptor antagonists and ANP receptor agonists are being studied and may provide future treatment options more closely related to the pathophysiology of these disorders.
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PMID:[The neuroendocrinology of stress and the pathophysiology and therapy of depression and anxiety]. 1262 45

There is considerable evidence that stress-related psychiatric disorders, including depression and post-traumatic stress disorder (PTSD), are associated with hypersecretion of corticotropin-releasing factor (CRF) within the central nervous system (CNS). One line of evidence that is consistent with central CRF hypersecretion in these disorders is the blunted adrenocorticotropin hormone (ACTH) response to intravenous CRF administration, likely a consequence, at least in part, of downregulation of anterior pituitary CRF receptors. The present study tests the hypothesis that elevated cerebrospinal fluid (CSF) concentrations of CRF and a secondary ACTH secretagogue, arginine vasopressin (AVP), are associated with diminished adenohypophyseal responses in a standard CRF stimulation test. CSF concentrations of CRF and AVP, and plasma ACTH responses to the administration of 1 microg/kg ovine CRF (oCRF) were measured in healthy adult women with and without current major depression and/or a history of significant childhood abuse. The primary outcome measure was ACTH area under the curve (AUC) in the CRF stimulation test. Multiple linear regression was performed to identify the impact of CSF CRF and AVP concentrations upon the pituitary response to CRF stimulation. The regression model explained 56.5% of the variation in the ACTH response to CRF stimulation. The relationship of CSF concentrations of CRF to ACTH responses to CRF were best described by a third-order function that was inversely correlated over most of the range of studied values. The association of ACTH response with CSF concentration of AVP and the dose of oCRF followed second-order kinetics. These findings support the hypothesis that central CRF hypersecretion is associated with a blunted ACTH response to exogenously administered CRF, explaining almost 60% of the variation in the ACTH response to CRF.
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PMID:Cerebrospinal fluid corticotropin-releasing factor (CRF) and vasopressin concentrations predict pituitary response in the CRF stimulation test: a multiple regression analysis. 1262 39

Stress activates the central and peripheral components of the stress system, i.e., the hypothalamic-pituitary-adrenal (HPA) axis and the arousal/sympathetic system. The principal effectors of the stress system are corticotropin-releasing hormone (CRH), arginine vasopressin, the proopiomelanocortin-derived peptides alpha-melanocyte-stimulating hormone and beta-endorphin, the glucocorticoids, and the catecholamines norepinephrine and epinephrine. Appropriate responsiveness of the stress system to stressors is a crucial prerequisite for a sense of well-being, adequate performance of tasks and positive social interactions. By contrast, inappropriate responsiveness of the stress system may impair growth and development, and may account for a number of endocrine, metabolic, autoimmune and psychiatric disorders. The development and severity of these conditions primarily depend on the genetic vulnerability of the individual, the exposure to adverse environmental factors and the timing of the stressful event(s), given that prenatal life, infancy, childhood and adolescence are critical periods characterized by increased vulnerability to stressors. The developing brain undergoes rapid growth and is characterized by high turnover of neuronal connections during the prenatal and early postnatal life. These processes and, hence, brain plasticity, slow down during childhood and puberty, and plateau in young adulthood. Hormonal actions in early life, and to a much lesser extent later, can be organizational, i.e., can have effects that last for long periods of time, often for the entire life of the individual. Hormones of the stress system and sex steroids have such effects, which influence the behavior and certain physiologic functions of individuals for life. Exposure of the developing brain to severe and/or prolonged stress may result in hyperactivity/hyperreactivity of the stress system, with resultant amygdala hyperfunction (fear reaction), decreased activity of the hippocampus (defective glucocorticoid-negative feedback, cognition), and the mesocorticolimbic dopaminergic system (dysthymia, novelty-seeking, addictive behaviors), hyperactivation of the HPA axis (hypercortisolism), suppression of reproductive, growth, thyroid and immune functions, and changes in pain perception. These changes may be accompanied by abnormal childhood, adolescent and adult behaviors, including excessive fear ('inhibited child syndrome') and addictive behaviors, dysthymia and/or depression, and gradual development of components of the metabolic syndrome X, including visceral obesity and essential hypertension. Prenatal stress exerted during the period of sexual differentiation may be accompanied by impairment of this process with behavioral and/or somatic sequelae. The vulnerability of individuals to develop varying degrees and/or components of the above life-long syndrome is defined by as yet unidentified genetic factors, which account for up to 60% of the variance. CRH has marked kindling and glucocorticoids have strong consolidating properties, hence both of these hormones are crucial in development and can alone produce the above syndrome. CRH and glucocorticoids may act in synergy, as in acoustic startle, while glucocorticoids may suppress or stimulate CRH, as in the hypothalamus and amygdala, respectively. A CRH type 1 receptor antagonist, antalarmin, inhibits both the development and expression of conditioned fear in rats, and has anxiolytic properties in monkeys. Profound stressors, such as those from sexual abuse, may elicit the syndrome in older children, adolescents and adults. Most frequently, chronic dysthymia and/or depression may develop in association with gastrointestinal complaints and/or the premenstrual tension syndrome. A lesser proportion of individuals may develop the classic posttraumatic stress disorder, which is characterized by hypocortisolism and intrusive and avoidance symptoms; in younger individuals it may present as dissociative personality disorder.
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PMID:Pediatric stress: hormonal mediators and human development. 1264 70

Many psychiatric disorders, including depression, post-traumatic stress disorder and other anxiety disorders, result from an interaction between genetic factors and exposure to a sufficiently sensitizing environmental stressor. The inbred Wistar Kyoto (WKY) rat strain has been proposed as a model of stress vulnerability, exhibiting an exaggerated hypothalamic-pituitary-adrenal (HPA) response to stress and susceptibility to gastric ulceration. Previously, we showed that stress-activation of the brain noradrenergic system was deficient in WKY rats, and they lacked noradrenergic facilitation of the HPA response in the lateral bed nucleus of the stria terminalis (BSTL), compared to outbred Sprague-Dawley (SD) controls. Deficient modulatory function of the noradrenergic system may contribute to the stress susceptibility of WKY rats. Thus, we investigated the influence of a sensitizing stimulus, chronic intermittent cold exposure, on neuroendocrine and noradrenergic stress reactivity, and on noradrenergic facilitation of the HPA response in these two strains. Chronic cold exposure (7 days, 4 h/day, 4 degrees C) potentiated activation of the HPA axis by acute immobilization stress, assessed by measuring plasma adrenocorticotropic hormone (ACTH), in both strains, although to a greater extent in WKY rats, and enhanced stress-induced norepinephrine (NE) release in BSTL of WKY but not SD rats. We then compared the influence of chronic cold exposure on noradrenergic modulation of the HPA stress response in BSTL, by measuring changes in acute stress-induced elevation of plasma ACTH after microinjecting the alpha(1)-adrenoreceptor antagonist benoxathian into the BSTL. As shown previously, benoxathian attenuated stress-induced ACTH secretion in control SD but not control WKY rats. After chronic cold, the ACTH response to acute stress was attenuated by benoxathian administration into BSTL of both strains, such that the WKY response was not different from that of SD rats. Thus, chronic cold not only sensitized the release of NE in BSTL of WKY rats, but also restored noradrenergic facilitation of their already-elevated HPA response. Such functional sensitization of a previously-deficient facilitatory system may be one mechanism whereby exposure to repeated or severe stress may induce pathologic dysregulation of the stress response in susceptible individuals, resulting in psychiatric illness.
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PMID:Chronic cold stress sensitizes brain noradrenergic reactivity and noradrenergic facilitation of the HPA stress response in Wistar Kyoto rats. 1269 37

Hypothalamic-pituitary-adrenocortical (HPA) axis data, such as low plasma cortisol concentrations in spite of increased corticotropin-releasing hormone (CRH) levels in patients with posttraumatic stress disorder (PTSD), are difficult to interpret. Atrial natriuretic peptide (ANP) may be an explanatory link in the neuroendocrine pathophysiology of the disorder, since it is a neuromodulator with antianxiety effects that inhibits HPA activity at multiple levels. Seventeen patients with chronic PTSD and 17 healthy control subjects were given 100 microg of human CRH at 3 p.m. ANP, adrenocorticotropic hormone (ACTH), and cortisol levels in plasma as well as blood pressure and heart rate were measured during basal conditions and after CRH stimulation. Basal ANP levels were significantly lower in PTSD patients in comparison with normal controls, but the response to CRH was undistinguishable. In contrast to our expectation, no significant differences in basal or CRH-stimulated ACTH or cortisol parameters could be observed. Systolic and diastolic blood pressures at baseline and after CRH were significantly elevated in PTSD patients. All group differences remained significant after controlling for basal blood pressure and/or body mass index. Our data do not support a role of ANP in abnormal HPA axis regulation in PTSD. However, the persistently low ANP plasma levels in PTSD patients despite elevated blood pressure may serve to facilitate anxiety behavior and have adverse long-term cardiovascular consequences. Further studies to assess ANP secretion in PTSD patients and to clarify its pathophysiological impact are needed.
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PMID:Endocrine and cardiovascular responses to corticotropin-releasing hormone in patients with posttraumatic stress disorder: a role for atrial natriuretic peptide? 1270 94

This study evaluated basal levels and responsiveness to exercise of plasma adrenocorticotropic hormone (ACTH), and serum thyroid stimulating hormone (TSH), growth hormone (GH) and cortisol among adolescents from two differentially exposed groups 6 1/2 years after the 1988 earthquake in Armenia. Severity of total PTSD and Category C and D symptoms were negatively correlated with baseline cortisol. Preexercise ACTH was significantly lower, and preexercise TSH higher, among adolescents with more exposure. Depressive symptoms were negatively correlated with baseline cortisol and positively with TSH. Mean GH, TSH, and cortisol levels in both groups fell within normal limits. The pre- to postexercise increase in GH, TSH, and cortisol suggests that exercise challenge may be useful in the field investigation of neurohormonal activity among traumatized individuals.
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PMID:Hypothalamic-pituitary-adrenal activity among Armenian adolescents with PTSD symptoms. 1289 13

Anxiety is a heterogeneous term encompassing not only state or trait characteristics but also a wide range of pathologies such as generalized anxiety disorders, phobias, panic and obsessive-compulsive disorders, acute stress disorder, and posttraumatic stress disorder. Given that diverse forms of anxiety exist, numerous animal models have been developed, which are considered to be useful in identifying mechanisms underlying anxiety states. Examples of such animal models include paradigms that assess the behavioral response to neurogenic (or painful stimuli) or psychogenic stressors or to cues that had previously been associated with painful stimuli. The present report presents data regarding the impact of stressors on corticotropin-releasing hormone (CRH), and relates these to changes in anxiety-like states. Specifically, we demonstrate that (1) psychogenic stressors influence the in vivo release of CRH at the central nucleus of the amygdala (CeA); (2) although CRH changes within the CeA are exquisitely sensitive to stressors, they are also elicited by positive stimuli; and (3) while treatment with diazepam attenuates behavioral signs of anxiety, the CRH release associated with a stressor is unaffected by the treatment. The position is offered that although release of CRH within the CeA is increased under stressful conditions, it is not a necessary condition for the consequent behavioral expression of anxiety-like reactions, at least not in minimally threatening situations. We suggest that the CRH responses at the CeA may be involved in a preparatory capacity and, as such, may accompany a range of emotionally significant stimuli, be they appetitive or aversive.
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PMID:Differential involvement of amygdaloid CRH system(s) in the salience and valence of the stimuli. 1465 75

Using overnight metyrapone and combined dexamethasone/metyrapone tests, hypothalamic-pituitary-adrenocortical (HPA) axis feedback regulation was characterised in 10 patients with post-traumatic stress disorder (PTSD) and 10 matched healthy comparison subjects. Significant treatment effects of both metyrapone and the combination of dexamethasone and metyrapone were observed for adrenocorticotropic hormone (ACTH), 11-deoxycortisol (11-DOC) and cortisol, but no differences between patients and comparison subjects emerged. Dose-response studies using metyrapone and glucocorticoid agonists are needed to further investigate HPA axis regulation in PTSD.
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PMID:Overnight metyrapone and combined dexamethasone/metyrapone tests in post-traumatic stress disorder: preliminary findings. 1516 45

Evidence suggests that individuals with posttraumatic stress disorder (PTSD) have an enhanced sensitization of the hypothalamic--pituitary--adrenocortical (HPA) axis. However, few studies in adolescents have been performed. Fourteen sexually abused adolescent inpatients with DSM-IV PTSD (12 female, two male; mean +/- SD age, 16.2 +/- 1.9 years) were compared with 14 adolescent hospitalized controls (11 female, three male; mean age, 15.7 +/- 2.0 years). All subjects underwent a standard dexamethasone suppression test (DST, 1 mg given orally at 2300 h) five days after admission. Baseline blood samples were obtained at 0800 h, and the following day, adrenocorticotropin (ACTH) and cortisol levels were measured at 0800, 1600, and 2300 h. Clinical assessment included the Impact of Event Scale, Stanford Acute Stress Reaction Questionnaire, Beck Depression Inventory, and Coping Inventory for Stressful Situations. Post-DST ACTH levels were significantly lower in PTSD than in control adolescents (at 0800 h: P < 0.005; at 1600 h: P < 0.001; at 2300 h: P < 0.05). In patients, post-DST cortisol levels were reduced but not significantly. No correlations were found between ACTH and cortisol levels and time elapsed since trauma. These results demonstrate that sexually abused adolescents with PTSD show ACTH hypersuppression to DST suggesting enhanced glucocorticoid receptor sensitivity in the pituitary.
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PMID:Increased adrenocorticotropin suppression following dexamethasone administration in sexually abused adolescents with posttraumatic stress disorder. 1528 7

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