Search results for "STRAINS"
showing 10 items of 589 documents
Effect of Intraperitoneal Sterile Urine Injection on Abdominal Myoelectrical Activity in the Spinal Rat Model
1991
The abdominal muscle reflex contractions in response to intraperitoneal injection of homologous sterile urine and acid, alkaline, hypo- and hyperosmolar solutions are studied in an acute spinal rat model by conventional and integrated electromyographic techniques. Intraperitoneal injection of homologous sterile urine causes a powerful and almost immediate abdominal muscle contracture of relative short duration. This response seems not to be related to urine pH or osmolarity, since only when solutions with extreme variations in these parameters are injected intraperitoneally are significant abdominal muscle contractions observed.
Frequency-dependent effects of activation and inhibition of protein kinase C on neurohypophysial release of oxytocin and vasopressin
1989
Isolated rat neurohypophyses were superfused in vitro and the release of vasopressin and oxytocin into the medium was determined by specific radioimmunoassays. Hormone secretion was increased by electrical stimulation of the pituitary stalk at different frequencies. The effects of several phorbol esters, known to activate (phorbol 12,13-dibutyrate, PDB) or not to affect (4a-phorbol 12,13-dideconate and phorbol 12-monoacetate) protein kinase C, and of the direct protein kinase C inhibitor 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H7) were tested. Electrical stimulation with 450 pulses caused the release of about 45 μU vasopressin and 55 μU oxytocin, when a frequency of 3 Hz was applied…
Combination of open field and elevated plus-maze: a suitable test battery to assess strain as well as treatment differences in rat behavior.
1998
Abstract 1. 1. A test battery consisting of a standard open field, an enriched open field and an elevated plus maze was used to study behavior in rats. 2. 2. Male rats of the strains PVG/OlaHsd (PVG) and Sprague-Dawely-Hsd (SPRD) (150–200g body wt) were used to assess interstrain differences as well as handling effects. In a subsequent experiment an other set of male PVG rats (150–200g body wt) treated either with diazepam or zolpidem was used to evaluate the test battery for pharmacological purposes. 3. 3. SPRD rats displayed higher motor activity levels and also higher levels of exploratory behavior than the PVG rats. In contrast plus-maze activity indicated more anxiety of SPRD than PVG …
Training-induced protection and effect of terminated training on exercise-induced damage and water content in mouse skeletal muscles.
1995
Muscle swelling in connection with training-induced protection against exercise-induced damage and the disappearance of the protective adaptation after termination of training was studied in male NMRI-mice, aged 8 weeks at the beginning of the experiment. Mice were randomly assigned to several different treatment groups (training, training-exercise, exercise, detraining, detraining-exercise, together with their respective controls). Training and prolonged exercise sessions were performed by running uphill (6 degrees) on a motor-driven treadmill. Muscle damage was estimated by the total activity of beta-glucuronidase and water content from the red parts of m. quadriceps femoris (MQF), m. sol…
Nonlinearities in amoxycillin pharmacokinetics. I. Disposition studies in the rat.
1992
Several features of amoxycillin pharmacokinetics in man are not well known in spite of the extensive clinical use of the antibiotic. In this paper it is demonstrated that amoxycillin disposition kinetics in rats is clearly nonlinear, and that this may be due mainly to its elimination mechanisms. At different intravenous bolus dose levels, and in steady-state perfusion studies, the most striking feature is an increased renal clearance as dose increases (from 3.5 to 7.0 mg kg-1 for intravenous bolus, and from 4.6 to 20.0 micrograms min-1 for intravenous perfusions). This phenomenon has been attributed to a saturation of the active renal tubular reabsorption of the antibiotic. When the intrave…
Dose-dependent metabolism and hepatic distribution of phenprocoumon in rats
1988
The dose-dependency of phenprocoumon disposition was determined in rats by iv administration of 0.1 and 1.0 mg/kg doses to separate groups of animals. The intrinsic clearance (unbound clearance) was 33% lower in the animals given 1.0 mg/kg dose than in the animals given 0.1 mg/kg dose. The apparent unbound volume of distribution was 55% lower and the elimination rate constant 54% higher in the high dose group than in the lower dose group. Binding of phenprocoumon to liver showed saturability with a two- to threefold higher apparent unbound fraction of phenprocoumon in liver in animals given the high dose in comparison to animals given the low dose.
Sex-related Differences in Disposition and Response to Phenprocoumon in Rats
1988
Abstract The pharmacokinetics and the pharmacological response to phenprocoumon have been studied in female and male inbred Lewis-Wistar rats. A significantly lower clearance was found in female than in male rats (7.9 ± 1.4 vs 24.5 ± 2.5 mL h−1 kg−1, respectively; t = 15.09, P < 0.001) as well as a lower apparent volume of distribution (288 ± 46 vs 617 ± 105 mL kg−1; t = 7.58, P < 0.001) and a longer half-life (25.5 ± 3.4 vs 17.5 ± 1.8 h; t = 5.16, P < 0.001). The binding of phenprocoumon was higher in female than in male rats (fu: 0.0096 ± 0.0008 vs 0.0124 ± 0.0007, respectively; t = 6.66, P < 0.001). The total (C) as well as the unbound concentration (Cu) neede…
In vivo studies on the antiandrogenic effects of cimetidine versus cyproterone acetate in rats
1981
To investigate the antiandrogenic action of cimetidine in vivo, prostatic androgen uptake and metabolism, spermatogenesis, morphology of the prostate and testes, and plasma hormone levels were studied using Sprague-Dawley rats, and the results were compared with the effects of cyproterone acetate or castration. Cimetidine and cyproterone acetate caused significant reduction in the weights of the ventral prostate and testes. The changes of ventral prostate were accompanied by a dose-related epithelial atrophy. No adverse effect on spermatogenesis was observed after treatment with cimetidine at daily doses of 50 mg/kg or cyproterone acetate of 10 mg/kg. Although cimetidine treatment induced a…
Sulpiride has an antiaggressive effect in mice without markedly depressing motor activity
1991
The atypical neuroleptic, sulpiride is a selective D2 antagonist, having a preferential action on mesolimbic regions. The effects of acute and chronic treatment with sulpiride on aggressive behaviour in male mice were studied using an ethologically based analysis. It was hypothesized that sulpiride would diminish "threat" and "attack" but would not produce marked "immobility", because of the mesolimbic effect referred to above. Isolated albino male mice (experimental animals) were confronted by "standard opponents". Acutely-treated experimental animals received an intraperitoneal injection of sulpiride (20, 50 or 100 mg/kg) 30 min before testing. Chronically-treated animals received sulpiri…
EFFECTS OF 4-AMINOPYRIDINE ON ACETYLCHOLINE OUTPUT FROM THE CEREBRAL CORTEX OF THE RAT in vivo
1982
Abstract 1 The effects of 4-aminopyridine (4AP) on the output of acetylcholine (ACh) from the cerebral cortex were investigated in unanaesthetized freely moving rats and in anaesthetized rats by means of the `cup technique'. ACh was determined by bioassay on the dorsal muscle of the leech. 2 In unanaesthetized rats intraperitoneal injection of 4AP (3 mg/kg) had no effect on the cortical output of ACh. 3 After injection of morphine (10 mg/kg s.c.), which depressed the spontaneous output of ACh, 4AP increased the cortical output to a level significantly higher than that determined before morphine injection. 4 In rats anaesthetized with either urethane or pentobarbitone, drugs known to decreas…