Search results for "STRAINS"
showing 10 items of 589 documents
Antidepressant and anxiolytic effects of alprazolam versus the conventional. antidepressant desipramine and the anxiolytic diazepam in the forced swi…
1992
The antidepressant and anxiolytic effects of alprazolam were compared to those of desipramine, diazepam and buspirone in the forced swim test. Subchronic alprazolam induced a reduction in immobility similar to that of desipramine in 'non-pretested' and 'pretested' rats. In 'non-pretested' rats, the anti-immobility effect of desipramine was potentiated by diazepam and alprazolam, given before subchronic desipramine, while the anti-immobility effect of subchronic alprazolam was counteracted by diazepam. Diazepam, administered before the pretest session, counteracted, 24 h later, the anti-immobility effect of subchronic desipramine and alprazolam; alprazolam counteracted the anti-immobility ef…
Induction of anamnestic T cell proliferation by antigen-pulsed, bone marrow-derived macrophages.
1981
Bone marrow-derived macrophages (BMM phi) were grown in a liquid culture system in the presence of L cell-conditioned medium as a source of colony-stimulating factor. After a 4-h pulse with antigen, cultured irradiated BMM phi were capable of presenting the antigen to primed T cells as assessed in a T cell proliferation assay. Proliferation was optimal when BMM phi were used between days 5 and 8 of bone marrow cell culture. T cells of Lyt1 and Lyt123 phenotype had to be present at the start of the culture period to yield an optimal response. Conventional antisera and monoclonal antibodies directed against the H-2 I region and the I-A subregion, respectively, proved inhibitory in this system…
Endogenous adenosine inhibits hippocampal CA1 neurones: further evidence from extra- and intracellular recording.
1988
Extracellular and intracellular recordings from CA1 pyramidal neurones of rats in vitro were used to study the effects of endogenous and exogenously applied adenosine. The adenosine receptor antagonist, caffeine, enhanced the intracellular recorded e.p.s.p.-i.p.s.p. sequence evoked by stimulation of the stratum radiatum which is antagonized by exogenous adenosine. The late, potassium dependent i.p.s.p. was not antagonized. The adenosine uptake inhibitor, nitrobenzylthioinosine (NBTI), mimicked the effects of exogenously applied adenosine. The effects of NBTI and of exogenously applied adenosine were antagonized by caffeine in the same manner. Exposure to adenosine deaminase enhanced the evo…
An electrophysiological study of the ontogenesis of adenosine receptors in the CA1 area of rat hippocampus
1990
Abstract The depressant effect of adenosine (Ad) was studied electrophysiologically in hippocampal slices from 5-, 10-, 15-, 20-, 30- and 120-day-old rats. Ad (10μM) depressed the field EPSP in CA1 to the same extent in all age groups. Caffeine (Caf), an Ad receptor antagonist, enhanced and nitrobenzylthioinosine (NBI), an Ad uptake blocker, depressed the field EPSP. Both these effects were, however, less prominent in slices from younger animals, a finding consistent with lower extracellular levels of endogenous Ad in neonatal rats.
Alpha-adrenergic modulation of glutathione metabolism in isolated rat hepatocytes.
1988
Glutathione metabolism was studied in isolated hepatocytes from 48-h starved rats. Phenylephrine (10 microM, final concentration) was incubated in the presence of a mixture of L-glutamine, glycine, L-serine, and L-methionine (at 10 times their normal plasma concentration). Alpha-adrenergic stimulation provoked a decrease in glutathione (GSH) synthesis. This effect was accompanied by an enhanced efflux of glutathione from the cells. Phenylephrine stimulated the rate of glutathione disulfide (GSSG) formation; however, this effect was clearly insufficient to explain the disappearance of GSH. Our results suggest that the decrease in cellular GSH levels observed under conditions of shock, stress…
Effect of aging on metabolic zonation in rat liver: acinar distribution of GSH metabolism.
1992
The effect of age on the glutathione antioxidant system and its acinar distribution in rat liver was studied. GSH/GSSG ratio in blood and liver was lower in old than in young rats. Hepatic glutathione peroxidase and glutathione S-transferase activities were higher in old than in young rats, whereas hepatic gamma-glutamyl transpeptidase activity was lower in old than in young rats. Glutathione reductase and glucose-6-phosphate dehydrogenase activities did not change with age in rat liver. Total glutathione levels and glutathione peroxidase activity were higher in periportal than in perivenous areas of young rats, but this heterogeneous distribution did not occur in old rats. No change with a…
Effects of training on regional substrate oxidation in the hearts of ageing rats.
1989
23-month-old male rats were trained by running for 20 weeks. The oxidation rates of succinate, glutamate+malate, palmitoylcarnitine, and pyruvate and the activities of lactate dehydrogenase, citrate synthase, isocitrate dehydrogenase and cytochrome oxidase were measured in the subendocardium and subepicardium and in the right ventricle. Regional differences of substrate oxidation rates in the myocardium of old sedentary or trained rats were less than in young rats, suggesting that regional differences in the cardiac work load disappear during ageing. Training did not improve oxidation rates, in contradiction to some previous results.
Effects of aging and life-long physical training on collagen in slow and fast skeletal muscle in rats. A morphometric and immuno-histochemical study.
1987
Intramuscular collagen in a slow (m. soleus) and a fast (m. rectus femoris) skeletal muscle was studied by biochemical, morphometric, and immunohistochemical methods. Wistar white rats of 1, 4, 10, and 24 months were used as experimental animals. Our aim was to evaluate the effects of life-long physical training (treadmill running, 5 days a week for 1, 3, 9, and 23 months depending on the age attained). The biochemical concentration of collagen was higher in m. soleus than in m. rectus femoris and it increased in youth and in old age in m. soleus. The trained rats had higher concentrations of collagen than the untrained rats at 10 and 24 months. The morphometrically measured area-fractions …
Electroretinographic response in WAG/Rij rats after low-intensity cyclic light exposure.
1993
In order to investigate the combined influence of age and light, the b-wave and oscillatory potentials (OPs) of the electroretinogram (ERG) were recorded in 1.5-, 7- and 12-month-old WAG/Rij rats, reared under homogenous low-intensity cyclic light exposure. Wistar albino rats of the same ages, reared under the same conditions, served as controls. The b-wave amplitude decreased, and its implicit time increased in the older age groups significantly more in WAG/Rij than in Wistar rats. Statistical analysis indicated that the b-wave amplitude is a more suitable parameter than implicit time in differentiating the ERG variations of one rat strain from the other. The added amplitude of the OPs als…
Effects of age and life-time physical training on fibre composition of slow and fast skeletal muscle in rats.
1987
The effects of age and endurance training on muscle fibre characteristics were studied in a slow (m. soleus, MS) and in a fast (m. rectus femoris, MRF) skeletal muscle. Wistar rats at ages of 1, 2, 4, 10, and 24 months were used as experimental animals. The trained rats were put to run on a motor-driven treadmill 5 d/wk beginning from the age of 1 month. The body weights of the animals increased continuously throughout their lives. The muscle weights increased up to the age of 10 months, after which they tended to decrease. The trained adult rats had lower body weights as well as lower muscle weights than the untrained adult rats. The amount of the intramuscular lipid decreased with age, es…