Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0003864 (arthritis)
 69,039 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Corticotropin-releasing hormone (CRH), the principal regulator of the hypothalamic-pituitary-adrenal axis, is also secreted in peripheral inflammatory sites, where it acts as a local proinflammatory agent. Arthritis-susceptible LEW/N rats have profoundly deficient hypothalamic CRH responses to inflammatory stimuli and other stressors. Arthritis-resistant F344/N rats, on the other hand, have a robust increase in hypothalamic CRH in response to the same stimuli. Contrasting with these hypothalamic CRH responses, we now show that CRH expression is markedly increased in the joints and surrounding tissues of LEW/N rats with streptococcal cell wall- and adjuvant-induced arthritis, whereas it is not increased in similarly treated F344/N rats and is only transiently increased in congenitally athymic nude LEW.rnu/rnu rats. Glucocorticoid treatment suppressed, but did not eliminate, CRH immunoreactivity in the joints of LEW/N rats. CRH mRNA was present in inflamed synovia, as well as in spinal cord, and inflamed synovia also expressed specific CRH-binding sites. We compared CRH expression in inflamed joints with another well-characterized proinflammatory neuropeptide, substance P (SP), and found that SP immunoreactivity paralleled that of CRH. In summary, although LEW/N rats have deficient hypothalamic CRH responses to inflammatory stimuli compared with F344/N rats, they express relatively high levels of CRH at the site of inflammation. Analogous to SP, CRH may be delivered to the inflammatory site by peripheral nerves and/or synthesized at the inflammatory site. These data provide further support for the concept that CRH not only triggers the pituitary-adrenal antiinflammatory cascade, but also functions as an antithetically active local mediator of acute and chronic inflammatory arthritis. These data also illustrate the complex interrelationships of the nervous, endocrine, immune, and inflammatory systems.
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PMID:Local secretion of corticotropin-releasing hormone in the joints of Lewis rats with inflammatory arthritis. 128 40

Corticotropin-releasing hormone (CRH) was initially sequenced and identified in 1981, and has since become established as the principal organizer of the stress response. It causes activation of the pituitary-adrenal axis, behavioural arousal, sympathetic stimulation and a decrease in appetite. In vitro studies have shown regulation of hypothalamic CRH by a variety of neuro-transmitters, including the cytokines interleukin-1 and interleukin-6. However, circulating CRH is mainly derived from extra-hypothalamic sites, and levels may be elevated in patients with tumours secreting ectopic CRH. The placenta is a further source of CRH, which may be specifically raised in patients with pre-eclampsia, and could be a factor in the initiation of parturition. The recently identified CRH binding protein may play a vital role in this process. Clinically, CRH testing has become extremely useful in the diagnosis and differential diagnosis of Cushing's syndrome, and particularly for the localization of ACTH following inferior petrosal sinus catheterization. There is considerable evidence that many patients with depressive illness may have a disturbance of the central control of CRH, and this may be become of increasing importance in the therapy of this common condition. There are also intriguing new data suggesting that abnormalities in CRH regulation may be involved in the pathogenesis of inflammatory arthritis.
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PMID:Corticotropin-releasing hormone in health and disease: an update. 141 42

Infections and injury are often accompanied by the production of large quantities of proinflammatory mediators such as cytokines and eicosanoids. These substances have been shown to efficiently activate the hypothalamic-pituitary-adrenocortical (HPA) system. The glucocorticoid hormones secreted from the adrenal cortex seem to be crucial for survival because they have an inhibitory influence on inflammatory processes, which, if uncontrolled, may become toxic for the host. Furthermore, these steroid hormones are known to support thermogenesis by inducing or repressing key enzymes of carbohydrate, lipid, and protein metabolism, and thus may also facilitate energy mobilization during fever, which usually accompanies infectious diseases. Finally, a number of studies suggest that glucocorticoids attenuate debilitating symptoms of inflammatory mediators, such as sleepiness, loss of appetite, and suppression of reproductive functions. One can assume that glucocorticoids exert similar behavioral effects during inflammatory conditions, which are seen in infectious diseases. Corticotropin-releasing hormone (CRH), the major hypothalamic component of the HPA system, is a putative mediator of the central effects of cytokines and autacoids because it inhibits growth, reproduction, and food intake. In contrast, CRH decreases sleep duration. Vasopressin, another hypothalamic peptide of the HPA system, counteracts fever and sickness behavior and is thought to support recovery from inflammatory diseases. Apparently, a well-balanced, concerted action of proinflammatory mediators, glucocorticoids, and hypothalamic peptide hormones provides not only an efficient principle for combating microorganisms and support of tissue repair but also for self-protection of the host during the stress of inflammation. Therefore, an impairment of the HPA system under inflammatory conditions often has severe pathological consequences, for example, in patients suffering from Addision's disease and arthritis.
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PMID:The role of the hypothalamic-pituitary-adrenocortical system during inflammatory conditions. 785 Aug 74

Adjuvant-induced arthritis results in chronic activation of the hypothalamo-pituitary-adrenal (HPA) axis. In the Piebald-Viral-Glaxo (PVG) rat, however, corticotropin-releasing factor (CRF) mRNA in the parvocellular paraventricular nucleus (pPVN) of the hypothalamus was reduced, and the normal corticosterone and CRF mRNA responses to acute stress were inhibited. The proenkephalin A mRNA response to stress in the pPVN was maintained, implying a specific inhibition of the CRF mRNA responses in this pathological situation. Adrenalectomy at day 0 (the time of adjuvant injection), day 13 (just before inflammation), or day 19 (submaximal inflammation) resulted in a marked increase in CRF mRNA compared with day 21 adrenal-intact arthritic animals. However, levels were below those of nonarthritic adrenalectomized rats, demonstrating that the inhibition of CRF mRNA associated with arthritis is not simply due to changes in glucocorticoid feedback. Proopiomelanocortin mRNA in the anterior pituitary was markedly increased in all adrenalectomized arthritic animals above the increase seen in sham-adrenalectomized day-21 arthritic rats. Adrenalectomy was always associated with an increase in the severity of the disease.
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PMID:HPA axis responses to acute stress and adrenalectomy during adjuvant-induced arthritis in the rat. 838 16

The corticotropin-releasing factor (CRF)-containing neurons of the parvocellular division of the hypothalamic paraventricular nucleus play a pivotal role in the regulation of the hypothalamo-pituitary-adrenal axis. We have studied the regulation of these neurons in the conscious rat using the technique of quantitative in situ hybridization histochemistry. Corticosteroid feedback reduces CRF mRNA levels in a dose-dependent manner, although even prolonged administration of very high doses cannot abolish CRF transcripts completely. Both physical and psychological stressors produce a robust and readily reproducible increase in CRF mRNA. These responses cannot be prevented by changes in circulating corticosteroids--a similar magnitude of response occurs with high basal levels in the adrenalectomized animal and with low basal levels during treatment with supraphysiological doses of glucocorticoid. Alterations in CRF mRNA levels in response to stress are, however, lost during the physiological condition of lactation, a state known to result in stress hyporesponsiveness, and also after 6-hydroxydopamine lesions to the catecholaminergic innervation of the paraventricular nucleus. We have also studied two conditions of chronic immunological activation of the hypothalamo-pituitary-adrenal axis--adjuvant-induced arthritis and experimental allergic encephalomyelitis. Both of these results in activation of the hypothalamo-pituitary-adrenal axis with increased plasma corticosterone and ACTH, and pituitary pro-opiomelanocortin (POMC) mRNA. Unexpectedly, however, the activation of pituitary corticotrophs does not seem to be a primary result of increased activation of the CRF neurons, which actually show a consistent fall in CRF mRNA.
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PMID:Expression of corticotropin-releasing factor mRNA in response to stress. 849 Oct 86

Susceptibility to arthritis in the Lewis rat is associated with a defect of the hypothalamic-pituitary-adrenal axis. We examined the pituitary corticotropes of both intact and dexamethasone-treated male and female inflammatory-disease-susceptible Lewis and inflammatory-disease-resistant Fischer rats. We determined adrenocorticotropin levels in the media from primary cultures of anterior pituitary cells of both strains. In other experiments we have measured intracellular cyclic adenosine monophosphate and inositol monophosphate accumulation. Cells were incubated with corticotropin-releasing hormone, arginine vasopressin, forskolin, phorbol myristate acetate, or thyrotropin-releasing hormone. Corticotropin-releasing hormone stimulated adrenocorticotropin secretion from both male and female Lewis rat pituitary cells in a concentration-dependent manner. Basal and stimulated adrenocorticotropin levels in cells from Lewis rats were lower than those measured in the incubation media of Fischer rat dispersed pituitary cells. Arginine vasopressin, as well as forskolin and phorbol myristate acetate, induced a significant release of adrenocorticotropin from pituitary cells of both strains. Incubation with corticotropin-releasing hormone did not produce a significant accumulation of intracellular cyclic adenosine monophosphate in Lewis rat dispersed pituicytes of both sexes. On the other hand, forskolin induced a significant increase of intracellular cyclic adenosine monophosphate in the same cultures. Finally, inositol monophosphate accumulation was comparable in pituitary cells from both Lewis and Fischer rats of both sexes incubated with thyrotropin-releasing hormone. Adrenocorticotropin secretion from pituitary cells of male Lewis rats treated in vivo with dexamethasone was either reduced or abolished following incubation with different secretagogues. A defect in pituitary adrenocorticotropin secretion could be among the causes of the hyporesponsiveness of the hypothalamic-pituitary-adrenal axis in the Lewis rat. Such a defect appears to be associated with dysfunction of receptor-coupled events related to adenylate cyclase.
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PMID:Adenylate-cyclase-dependent pituitary adrenocorticotropin secretion is defective in the inflammatory-disease-susceptible Lewis rat. 873 85

A stress-free automated blood sampling system has been employed to demonstrate pulsatile hypothalamo-pituitary-adrenal (HPA) activity in the rat. In females, pulses of corticosterone secretion occur approximately once/hour throughout the 24 h cycle, with variation in pulse amplitude underlying a diurnal rhythm. Males show smaller pulses of secretion which become widely spaced during the early light phase nadir. Ageing does not affect the occurrence of pulses but the diurnal variation is lost. Analysis of the relationship between the HPA response to an acute noise stress and its coincidence with the various phases of the pulse, suggests that pulsatile activity arises from alternating periods of activation and suppression. Responses to i.v. corticotropin-releasing factor are not affected by pulse phase, indicating that this relationship is not generated at the pituitary-adrenal level. This phase relationship holds for all strains of rat except the hyperresponsive Fischer-344 in which an exaggerated stress response arises from a lack of phase-dependent suppression. Patterns of pulsatile activity are also modulated by neonatal programming or chronic HPA activation arising from adjuvant-induced arthritis, with consequent impact upon the response to acute stimuli. Thus, variations in the patterns of pulsatile activity are important determinants of both basal secretion and acute responses of the HPA axis.
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PMID:Significance of pulsatility in the HPA axis. 1075 74

Mast cells are critical for allergic reactions, but also for innate or acquired immunity and inflammatory conditions that worsen by stress. Corticotropin-releasing hormone (CRH), which activates the hypothalamic-pituitary-adrenal axis under stress, also has proinflammatory peripheral effects possibly through mast cells. We investigated the expression of CRH receptors and the effects of CRH in the human leukemic mast cell (HMC-1) line and human umbilical cord blood-derived mast cells. We detected mRNA for CRH-R1alpha, 1beta, 1c, 1e, 1f isoforms, as well as CRH-R1 protein in both cell types. CRH-R2alpha (but not R2beta or R2gamma) mRNA and protein were present only in human cord blood-derived mast cells. CRH increased cAMP and induced secretion of vascular endothelial growth factor (VEGF) without tryptase, histamine, IL-6, IL-8, or TNF-alpha release. The effects were blocked by the CRH-R1 antagonist antalarmin, but not the CRH-R2 antagonist astressin 2B. CRH-stimulated VEGF production was mediated through activation of adenylate cyclase and increased cAMP, as evidenced by the fact that the effect of CRH was mimicked by the direct adenylate cyclase activator forskolin and the cell-permeable cAMP analog 8-bromo-cAMP, whereas it was abolished by the adenylate cyclase inhibitor SQ22536. This is the first evidence that mast cells express functional CRH receptors and that CRH can induce VEGF secretion selectively. CRH-induced mast cell-derived VEGF could, therefore, be involved in chronic inflammatory conditions associated with increased VEGF, such as arthritis or psoriasis, both of which worsen by stress.
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PMID:Human mast cells express corticotropin-releasing hormone (CRH) receptors and CRH leads to selective secretion of vascular endothelial growth factor. 1594 67

Corticotropin-releasing hormone (CRH) coordinates the systemic stress response via hypothalamic-pituitary-adrenal (HPA) axis activation with subsequent modulation of the inflammatory response. Stress is known to affect expression of immune-mediated inflammatory diseases, many of which are associated with HPA axis abnormalities. HPA axis components including CRH and its receptors (CRH-R) exist in the skin and exhibit differential expression according to cell type, physiological fluctuations and disease states. This confirms a local functioning cutaneous HPA-like system. Peripheral CRH may exhibit proinflammatory effects. Animal studies confirm that peripheral CRH is required for induction of the inflammatory response in vivo. CRH and CRH-R are upregulated in inflammatory arthritis synovium and psoriatic skin. CRH may influence mast cell activation, direct modulation of immune cells, angiogenesis and induction of the novel orphan nuclear receptor NURR1. This transcription factor is part of the steroid/thyroid superfamily of related nuclear receptors that includes receptors for steroids, retinoids and vitamin D; ligands of these receptors are effective in treating psoriasis. The roles of CRH and NURR1 in psoriasis and inflammatory skin diseases, especially those associated with stress, remain to be elucidated. This stress may be psychological or physical. CRH, produced locally or delivered by peripheral nerves, may mediate interactions between a cutaneous HPA axis-like system and the central HPA axis--the "brain-skin axis".
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PMID:The role of corticotropin-releasing hormone in immune-mediated cutaneous inflammatory disease. 1648 Apr 21

As a hormone in the hypothalamic-pituitary-adrenocortical (HPA) axis corticotropin-releasing factor (CRF) mediates stress responses. CRF can also act as a neuromodulator of synaptic transmission outside the HPA axis. A major site of extrahypothalamic expression of CRF and its G-protein-coupled receptors is the amygdala, a key player in affect-related disorders such as anxiety. The laterocapsular division of the central nucleus of the amygdala (CeLC) is important for the modulation of pain affect. This study determined the effects of CRF1 and CRF2 receptor antagonists in CeLC neurons in an arthritis pain model. Extracellular single-unit recordings were made from CeLC neurons in anesthetized adult rats. All neurons responded more strongly to noxious than to innocuous mechanical stimulation (compression) of peripheral tissues, including the knee. Evoked responses and background activity were measured before and during the development of a kaolin/carrageenan-induced knee joint arthritis. Drugs were administered into the CeLC by microdialysis before and/or after arthritis induction. All CeLC neurons showed increased responses to mechanical stimuli ("sensitization") 5-6 h postinduction of arthritis. A selective CRF1 receptor antagonist (NBI27914; 1-100 microM, concentration in microdialysis probe; 15 min) inhibited evoked responses and background activity in arthritis (n = 9) but had no effect under normal conditions before arthritis (n = 9). In contrast, a selective CRF2 receptor antagonist (Astressin-2B; 1-100 microM, 15 min) had no effect in arthritis (n = 7) but increased the neurons' responses under normal conditions (n = 8). These data suggest that CRF1 receptors in the amygdala contribute to pain-related sensitization, whereas the normally inhibitory function of CRF2 receptors is lost in the arthritis pain model.
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PMID:Differential effects of CRF1 and CRF2 receptor antagonists on pain-related sensitization of neurons in the central nucleus of the amygdala. 1739 12


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