Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0848237 (acute stress)
 4,619 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Although cannabinoids exert strong effects on brain function, there have been no extensive analyses of the long-term effects of cannabinoids on mammalian brain structure. Consequently, we conducted quantitative light and electron microscopic studies on the brains of rats treated chronically with delta 9-tetrahydrocannabinol (THC) (5 X weekly for 8 months--approximately 30% of the life-span). In these studies, we found significant THC-induced changes in hippocampal structure: specifically, THC-treated animals exhibited decreased neuronal density and increased glial cell reactivity (i.e. an increase of cytoplasmic inclusions). In addition, we confirmed prior reports of THC-induced increases in adrenal-pituitary activity, since both adrenocorticotropic hormone (ACTH) and corticosterone were elevated substantially during an acute stress. However, the animals appeared to be only minimally affected behaviorally by the doses used (highest dose: 8 mg/kg) and no effects of THC were observed on several ultrastructural variables, including synaptic density. The observed hippocampal morphometric effects of chronic THC are similar to apparent glucocorticoid-dependent changes that previously have been found to develop in rat hippocampus during normal aging. Given that cannabinoids and steroids are similar in chemical structure in several respects, therefore, the present results seem to raise the possibility that chronic THC exposure may alter hippocampal anatomical structure by interactions with, or mimicry of, adrenal steroid activity.
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PMID:Quantitative changes in hippocampal structure following long-term exposure to delta 9-tetrahydrocannabinol: possible mediation by glucocorticoid systems. 283 17

Although vocal mimicry in songbirds is well documented, little is known about the function of such mimicry. One possibility is that the mimic produces the vocalisations of predatory or aggressive species to deter potential predators or competitors. Alternatively, these sounds may be learned in error as a result of their acoustic properties such as structural simplicity. We determined the mimetic repertoires of a population of male spotted bowerbirds Ptilonorhynchus maculatus, a species that mimics predatory and aggressive species. Although male mimetic repertoires contained an overabundance of vocalisations produced by species that were generally aggressive, there was also a marked prevalence of mimicry of sounds that are associated with alarm such as predator calls, alarm calls and mobbing calls, irrespective of whether the species being mimicked was aggressive or not. We propose that it may be the alarming context in which these sounds are first heard that may lead both to their acquisition and to their later reproduction. We suggest that enhanced learning capability during acute stress may explain vocal mimicry in many species that mimic sounds associated with alarm.
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PMID:The mimetic repertoire of the spotted bowerbird Ptilonorhynchus maculatus. 2149 71

Stimulation of peripheral nociceptors leads to releasing of some mediators such as substance P (SP) and Calcitonin gene-related peptide (CGRP) and contributes to the edema formation by vasodilatation induction. On the other hand glucocorticoids have anti-inflammatory action, and they are elevated in the plasma during stress. This communication reports C-fibers inflammatory role and the effects of chronic and acute stress and/or dexamethasone (as stress mimicry) on paw edema induced by formalin at presence/deficit C-fibers rats. Acute stress and dexamethasone and chronic dexamethasone have shown an anti-inflammatory effect in C-normal groups, but chronic stress had no effect on inflammation. C-fibers reduction (C-lesion) had anti-inflammatory effects. In deficit C-fibers rats, acute and chronic stress had not stronger anti-inflammatory effect, but acute dexamethasone reduced the anti-inflammatory effect of C-fibers reduction while in the same condition, chronic dexamethasone induced stronger anti-inflammatory effect. The results show C-fiber nerve produce and release the peripheral inflammatory mediators, "C-fibers reduction" decreased the paw inflammation. Counter adaptation in C-lesion animals may reduce the modulatory effects of dexamethasone on the remaining C-fibers. Acute dexamethasone diminished the "C-fibers reduction" anti-inflammatory effect, but at chronic treatment, the modulatory effects of dexamethasone aggregated and it augmented the C-fibers reduction antiinflammatory effect.
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PMID:Role of C-fibers during acute and chronic stress on formalin-induced paw edema in rats. 2314 21