Search results for "Prague"
showing 10 items of 652 documents
Influence of photoperiodic history on clock genes and the circadian pacemaker in the rat retina
2006
The influence of seasonal lighting conditions on expression of clock genes and the circadian pacemaker was investigated in the rat retina. For this purpose, the 24-h profiles of nine clock genes (bmal1, clock, per1, per2, per3, dec1, dec2, cry1 and cry 2) and the arylalkylamine N-acetyltransferase gene as an indicator of the circadian pacemaker output were compared between light-dark periods of 8 : 16 and 16 : 8 h. The photoperiod influenced the daily patterns of the amount of transcript for per1, per3, dec2 and arylalkylamine N-acetyltransferase. This indicates that photoperiodic information modulates clock gene expression in addition to the circadian pacemaker of the retina. Under constan…
Photoreceptor cells display a daily rhythm in the orphan receptor Esrrβ
2015
Purpose Nuclear orphan receptors are critical for the development and long-term survival of photoreceptor cells. In the present study, the expression of the nuclear orphan receptor Esrrβ—a transcriptional regulator of energy metabolism that protects rod photoreceptors from dystrophy—was tested under daily regulation in the retina and photoreceptor cells. Methods The daily transcript and protein amount profiles were recorded in preparations of the whole retina and microdissected photoreceptor cells using quantitative PCR (qPCR) and western blot analysis. Results Esrrβ displayed a daily rhythm with elevated values at night in the whole retina and enriched photoreceptor cells. Daily regulation…
A nitrergic projection from the superior olivary complex to the inferior colliculus of the rat
2003
The present study was conducted to test whether the ascending auditory projection from the superior olivary complex (SOC) of the brainstem to the inferior colliculus (IC) may use nitric oxide (NO) as a neuroactive compound. We identified olivo-collicular projection neurons in subnuclei of the SOC by retrograde neuronal tracing with Fluoro-Gold (FG) injected into the central nucleus of the IC. Sections containing retrograde labelled neurons were subjected to immunohistochemical incubation in an antiserum directed against the enzyme responsible for NO production in nerve cells, neuronal NO synthase (nNOS). The analysis showed that FG-containing neurons as well as nNOS-immunoreactive neurons w…
Modulation of Spatial O2Tension Distribution in Experimental Tumors by Increasing Arterial O2Supply
1995
Tumor oxygenation has been measured polarographically in s.c. implanted DS-sarcomas on the dorsum of the hind foot of male Sprague-Dawley rats. pO2 was determined in all 3 spatial dimensions and 3-dimensional pO2 distributions as well as the mean extent of confluent areas with pO25 mmHg were calculated. Finally, the effect of elevating arterial pO2 (by carbogen breathing) as well as of increasing tumor blood flow (by angiotensin infusion) on the spatial pO2 distribution was analyzed. Depending on the tumor volume, the spatial pO2 distribution is more or less anisotropic. In smaller tumors, areas with physiological pO2 values are found adjacent to large hypoxic areas whereas larger tumors ar…
Differences in the nitric oxide/soluble guanylyl cyclase signalling pathway in the myocardium of neonatal and adult rats
2000
Abstract The effects of a nitric oxide-donor, S -nitroso- N -acetylpenicillamine, and a direct activator of soluble guanylyl cyclase, 3-(5′-hydroxymethyl-2′-furyl)-1-benzyl indazole (YC-1), on force of contraction ( F c ) and L-type Ca 2+ currents ( I Ca(L) ) were investigated in myocardial preparations from neonatal and adult rats. Since hearts from adult and neonatal animals contained 160 and 47 mg/100 g wet weight myoglobin, respectively, its possible interaction with both drugs was also investigated. Both S -nitroso- N -acetylpenicillamine (100 μM) and YC-1 (30 μM) were ineffective in myocardial preparations from adult rats but reduced the magnitude of I Ca(L) and F c in preparations fr…
Learning to learn: Theta oscillations predict new learning, which enhances related learning and neurogenesis
2011
Animals in the natural world continuously encounter learning experiences of varying degrees of novelty. New neurons in the hippocampus are especially responsive to learning associations between novel events and more cells survive if a novel and challenging task is learned. One might wonder whether new neurons would be rescued from death upon each new learning experience or whether there is an internal control system that limits the number of cells that are retained as a function of learning. In this experiment, it was hypothesized that learning a task that was similar in content to one already learned previously would not increase cell survival. We further hypothesized that in situations in…
State-dependent changes in auditory sensory gating in different cortical areas in rats.
2015
Sensory gating is a process in which the brain's response to a repetitive stimulus is attenuated; it is thought to contribute to information processing by enabling organisms to filter extraneous sensory inputs from the environment. To date, sensory gating has typically been used to determine whether brain function is impaired, such as in individuals with schizophrenia or addiction. In healthy subjects, sensory gating is sensitive to a subject's behavioral state, such as acute stress and attention. The cortical response to sensory stimulation significantly decreases during sleep; however, information processing continues throughout sleep, and an auditory evoked potential (AEP) can be elicite…
Phenylamides of 1-Phenyl (or Methyl)-5-benzamidopyrazole-4-carboxylic Acid as Vratizolin Analogs with Analgesic and Antiinflammatory Activities
2001
A number of phenylamides of 5-benzamidopyrazole-4-carboxylic acid were prepared in 50-80 % yields from 1-phenyl (or methyl) 6-phenylpyrazolo[3,4-d]1,3-oxazin-4(1H)-ones and aniline derivatives. All the compounds were tested for their analgesic and antiinflammatory activities, as well as for their ulcerogenic potential and acute toxicity. Some derivatives, when compared to phenylbutazone, proved more active in the tests for analgesie and antiexudative activities, but less active in the carrageenin paw oedema test. The compounds proved to posses marginal or no ulcerogenic effect, as well as low systemic toxicity.
Using simple interrupted suture anastomoses may impair translatability of experimental rodent oesophageal surgery
2019
Background/purpose: Irreproducibility and missing translatability are major drawbacks in experimental animal studies. Hand-sewn anastomoses in oesophageal surgery are usually continuous, whereas th...
Day- and night-time contents of monoamines and their metabolites in the medial preoptic area of the rat hypothalamus.
1999
The present study was conducted to investigate whether monoamines and their metabolites in the medial preoptic area (mPOA) of the rat hypothalamus exhibit differences in their contents between day and night. We therefore sampled the mPOA from adult animals of either sex at the middle of the light or dark period, respectively, and analyzed the tissue by means of high performance liquid chromatography with electrochemical detection. We found that, in female animals at mid-night, dopamine and 3,4-dihydroxyphenyl acetic acid (DOPAC) was reduced to 43 and 30%, respectively, of daytime levels, while the norepinephrine content was doubled. No significant differences were observed in male animals. …