Search results for "Wistar"
showing 10 items of 1094 documents
Increased Hypoxic Tolerance by Chemical Inhibition of Oxidative Phosphorylation: “Chemical Preconditioning”
1997
A short ischemic episode preceding sustained ischemia is known to increase tolerance against ischemic cell death. We report early-onset long-lasting neuroprotection against in vitro hypoxia by preceding selective chemical inhibition of oxidative phosphorylation: “chemical preconditioning.” The amplitude of CA1population spikes (psap) in hippocampal slices prepared from control animals (control slices) was 31 ± 27% (mean ± SD) upon 45-min recovery from 15-min in vitro hypoxia. In slices prepared from animals treated in vivo with 20 mg/kg 3-nitropropionate (3-np) 1–24 h prior to slice preparation (preconditioned slices), psap improved to 90 ± 15% (p < 0.01). Posthypoxic oxygen free radical…
Neurosteroid modulation of the presynaptic NMDA receptors regulating hippocampal noradrenaline release in normal rats and those exposed prenatally to…
2003
Abstract Prenatal exposure to diazepam (DZ), a positive allosteric modulator of the γ-aminobutyric acidA (GABAA) receptor complex, exerts profound effects that become more evident during puberty and in many cases are sex-specific, suggesting that such exposure interferes with the activity of steroid hormones. Apart from their well known effects on the genome, the reduced metabolites of many steroid hormones also interact directly with membrane receptors, including those for N-methyl- d -aspartate (NMDA). In this study, we compared the effects of several neurosteroids on NMDA receptors from normal rats and those exposed in utero to DZ (1.25 mg/kg per day) from the 14th through the 20th day o…
The role of pregnenolone sulphate in spatial orientation-acquisition and retention: An interplay between cognitive potentiation and mood regulation
2013
Abstract Neurosteroids can alter neuronal excitability interacting with specific neurotransmitter receptors, thus affecting several functions such as cognition and emotionality. In this study, we investigated, in adult male rats, the effects of the acute administration of pregnenolone-sulfate (PREGS) (10 mg/Kg, s. c.) on cognitive processes using the Can test, a non aversive spatial/visual task which allows the assessment of spatial information-acquisition during the baseline training, and of memory retention in the longitudinal study. Furthermore, on the basis of PREGS pharmacological profile, the modulation of depressive-like behaviour was also evaluated in the forced swim test (FST). Our…
Id2 leaves the chromatin of the E2F4-p130-controlled c-myc promoter during hepatocyte priming for liver regeneration
2006
The Id (inhibitor of DNA binding or inhibitor of differentiation) helix–loop–helix proteins are involved in the regulation of cell growth, differentiation and cancer. The fact that the molecular mechanisms of liver regeneration are not completely understood prompted us to study the fate of Id2 in proliferating liver. Id2 increases in liver regeneration after partial hepatectomy, following the early induction of its gene. Co-immunoprecipitation shows that Id2 forms a complex with E2F4, p130 and mSin3A in quiescent liver and all these components are present at the c-myc promoter as shown using ChIP (chromatin immunoprecipitation). Activation of c-myc during hepatocyte priming (G0–G1 transitio…
Neuroprotection of lipoic acid treatment promotes angiogenesis and reduces the glial scar formation after brain injury
2012
After trauma brain injury, a large number of cells die, releasing neurotoxic chemicals into the extracellular medium, decreasing cellular glutathione levels and increasing reactive oxygen species that affect cell survival and provoke an enlargement of the initial lesion. Alpha-lipoic acid is a potent antioxidant commonly used as a treatment of many degenerative diseases such as multiple sclerosis or diabetic neuropathy. Herein, the antioxidant effects of lipoic acid treatment after brain cryo-injury in rat have been studied, as well as cell survival, proliferation in the injured area, gliogenesis and angiogenesis. Thus, it is shown that newborn cells, mostly corresponded with blood vessels …
Molecular mechanisms of Id2 down-regulation in rat liver after acetaminophen overdose. Protection by N-acetyl-L-cysteine.
2010
Id2 is a pleiotropic protein whose function depends on its expression levels. Id2-deficient cells show increased cell death. This study explored the molecular mechanisms for the modulation of Id2 expression elicited by GSH and oxidative stress in the liver of acetaminophen (APAP)-intoxicated rats. APAP-overdose induced GSH depletion, Id2 promoter hypoacetylation, RNApol-II released and, therefore, Id2 down-regulation. Id2 expression depends on c-Myc binding to its promoter. APAP-overdose decreased c-Myc content and binding to Id2 promoter. Reduction of c-Myc was not accompanied by decreased c-myc mRNA, suggesting a mechanism dependent on protein stability. Administration of N-acetyl-cystein…
Differential alterations in the small intestine epithelial cell turnover during acute and chronic infection with Echinostoma caproni (Trematoda)
2015
Background The intestinal epithelium plays a multifactorial role in mucosal defense. In this sense, augmented epithelial cell turnover appears as a potential effector mechanism for the rejection of intestinal-dwelling helminths. Methods A BrdU pulse-chase experiment was conducted to investigate the infection-induced alterations on epithelial cell kinetics in hosts of high (mouse) and low (rat) compatibility with the intestinal trematode Echinostoma caproni. Results High levels of crypt-cell proliferation and tissue hyperplasia were observed in the ileum of infected mice, coinciding with the establishment of chronic infections. In contrast, the cell migration rate was about two times higher …
Characterization of rat glutathione transferases in olfactory epithelium and mucus
2019
International audience; The olfactory epithelium is continuously exposed to exogenous chemicals, including odorants. During the past decade, the enzymes surrounding the olfactory receptors have been shown to make an important contribution to the process of olfaction. Mammalian xenobiotic metabolizing enzymes, such as cytochrome P450, esterases and glutathione transferases (GSTs), have been shown to participate in odorant clearance from the olfactory receptor environment, consequently contributing to the maintenance of sensitivity toward odorants. GSTs have previously been shown to be involved in numerous physiological processes, including detoxification, steroid hormone biosynthesis, and am…
Disturbed social behavior and motivation in rats selectively bred for deficient sensorimotor gating
2007
Deficient prepulse inhibition (PPI) of startle reflects disturbed sensorimotor gating found in certain neuropsychiatric disorders. We here tested whether rats selectively bred for deficient PPI are deteriorated in behavioral paradigms used to model negative symptoms of schizophrenia. Rats with low PPI preferred standard rat-chow when having the choice between lever-pressing for reward-pellets or freely available rat-chow, suggesting reduced motivation. Additionally, these rats show deteriorated social behavior during interaction with a juvenile rat. Rats selectively bred for low PPI may therefore be used as a model to study the biological mechanisms and therapeutic strategies of negative sy…
Inhibition of Trypanosoma cruzi by plant extracts used in Chinese medicine.
2004
In this work, we assessed the effect of extracts obtained from 17 plants used in traditional Chinese medicine. These extracts were tested in vitro with the epimastigote form of Trypanosoma cruzi, clone Bra C(15) C(2), at 27 degrees C in F-29 medium at a concentration of 100 microg/ml in axenic cultures. Allopurinol was used as reference drug. Seven plant extracts showed inhibitory activities lower than 25%. Pueraria lobata, Mahonia beaei, Dictamus dasycarpus, Kochia scoparia, Sophora flavescens and Ligustrum lucidum showed effects with inhibition values between 25% and 60%, whereas Lithospermum erythrorhizon, Saussurea lappa, Melia toosendan and Cinnamomum cassia showed the greatest inhibit…