Search results for "Wistar"
showing 10 items of 1094 documents
Inhibitory effects of N-valproyl-L-tryptophan on high potassium, low calcium and low magnesium-induced CA1 hippocampal epileptiform bursting activity…
2012
N-valproyl-l-tryptophan (VPA-Tryp), new antiepileptic drug, was tested on CA1 hippocampal epileptiform bursting activity obtained by increasing potassium and lowering calcium and magnesium concentrations in the fluid perfusing rat brain slices. Each slice was treated with a single concentration (0.2, 0.5, 1 or 2 mM) of Valproate (VPA) or VPA-Tryp. Both burst duration and interburst frequency during and after treatment were off-line compared with baseline values. For both parameters, the latency and the length of statistically significant response periods as well as the magnitude of drug-induced responses were calculated. VPA-Tryp evoked fewer and weaker early excitatory effects than VPA on …
Labetalol absorption kinetics: Rat small intestine and colon studies
2006
Labetalol is a widely used drug for the management of hypertension, which is preferably administered by the oral route despite its low bioavailability. The objective of this study is to ascertain the mechanisms underlying its absorption as an approach to help in predicting the influence of dosage changes, possible drug-drug and drug-fruit juice interactions. Perfusion experiments have been performed in rats in two sites of absorption: the intestine and the colon. The nonlinearity of the process has been established by means of the assay of a wide range of concentrations (2-2000 microM). Fitting of the concentration versus time data allows the estimation of passive diffusion constant in the …
A novel miniature telemetric system for recording EEG activity in freely moving rats
2008
Telemetric recording systems offer the advantage to monitor physiological parameters in freely moving animals without any restrictions in their explorative behaviour. We present a novel, inexpensive, portable and reusable telemetric system to record the electroencephalogram (EEG) from adult freely moving rats under various experimental conditions. Our system consists of an implantable transmitter which communicates at a sampling rate of 500 Hz bi-directional with a receiver via radio transmission (in EU: 868.35 MHz; in USA: 916.5 MHz) over a distance of up to 3 m. The switching time between receiving and transmitting signals is 20s and the data transmission rate amounts to 115.2 kbps. The r…
The Janus face of chlorogenic acid on vascular reactivity: A study on rat isolated vessels
2016
Abstract Background Chlorogenic acid (CGA), the main polyphenol contained in coffee, is a major contributor to dietary polyphenol intake. Few studies reported its anti-hypertensive properties but the mechanisms are still indefinite. Purpose The present study assessed the direct effect of CGA in endothelium denuded or intact aortic rings from male Wistar rats and the mechanisms involved. Methods/Results CGA induced a direct endothelium-dependent relaxation that was significantly reduced by L-NAME (10 −4 M), indomethacin (10 −5 M) and combination of apamin (10 −7 M) and charybdotoxin (10 −7 M). Incubation of rings with CGA induced a dual effect on agonist-induced vasorelaxation. At 10 −6 …
Diabetic Goto Kakizaki rats as well as type 2 diabetic patients show a decreased diurnal serum melatonin level and an increased pancreatic melatonin-…
2006
There are functional inter-relationships between the beta cells of the endocrine pancreas and the pineal gland, where the synchronizing circadian molecule melatonin originates. The aim of this study was to elucidate a putative interaction between insulin and melatonin in diabetic patients and a diabetic rat model. We analyzed glucose, insulin, and melatonin levels of type 2 patients, as well as type 2 diabetic Goto Kakizaki (GK) rats by radioimmunoassay. Expression of pancreatic melatonin and pineal insulin receptors, as well as arylalkylamine-N-acetyltransferase (AANAT), was determined by real-time reverse transcriptase polymerase chain reaction (RT-PCR). The AANAT enzyme activity was meas…
Acute sodium depletion modifies septo-preoptic neuron sensitivities to neurohormones.
1998
Sodium (Na+) depletion induces sodium appetite to replenish Na+ loss. It appears to be a consequence of enhanced levels of aldosterone (Aldo) and angiotensin II (AII) in the plasma as well as in the brain. Mineralocorticoid pretreatment modifies the sensitivity of septo-preoptic neurons to locally applied AII and Aldo. Therefore, we investigated septo-preoptic neuronal sensitivities to AII and Aldo, as well as to the specific AII type-1 receptor (AT-1) non-peptide antagonist losartan (Los) and to the specific AII type-2 receptor (AT-2) non-peptide antagonist PD123319 after one Na+ depletion without repletion. We found that one Na+ depletion induced increases in the proportion of neurons inh…
Receptor identification and physiological characterisation of glucagon-like peptide-2 in the rat heart.
2010
Abstract Background and aims The anorexigenic glucagon-like peptide (GLP)-2 is produced by intestinal L cells and released in response to food intake. It affects intestinal function involving G-protein-coupled receptors. To verify whether GLP-2 acts as a cardiac modulator in mammals, we analysed, in the rat heart, the expression of GLP-2 receptors and the myocardial and coronary responses to GLP-2. Methods and results GLP-2 receptors were detected on ventricular extracts by quantitative real-time polymerase chain reaction (Q-RT-PCR) and Western blotting. Cardiac GLP-2 effects were analysed on Langendorff perfused hearts. Intracellular GLP-2 signalling was investigated on Langendorff perfuse…
Acute effects of three isoflavone class phytoestrogens and a mycoestrogen on cerebral microcirculation.
2007
Phytoestrogens and mycoestrogens are naturally occurring plant and fungus secondary metabolites with estrogen-like structure and/or actions. We aimed to check the hypothesis that phytoestrogens and mycoestrogens, due to their ability to elicit cerebral vasodilation, can induce acute increases in brain blood perfusion. For this purpose, we continuously recorded cerebrocortical perfusion by laser-Doppler flowmetry in anesthetized rats receiving intracarotid infusions (1 mg/kg) of one of the following estrogenic compounds: biochanin A, daidzein, genistein or zearalanone. We have shown the ability of two isoflavone class phytoestrogens (daidzein and biochanin A) and the mycoestrogen zearalanone…
Ethanol Modulates Corticotropin Releasing Hormone Release From the Rat Hypothalamus: Does Acetaldehyde Play a Role?
2010
BACKGROUND AND METHODS Ethanol (EtOH) activates hypothalamic-pituitary-adrenal (HPA) axis, resulting in adrenocorticotropin hormone, glucocorticoid release, and in modifications of the response of the axis to other stressors. The initial site of EtOH action within the HPA system seems to be the hypothalamus. Thus, to determine the mechanisms responsible for these effects, we investigated: (i) whether EtOH was able to release corticotrophic releasing hormone (CRH) from incubated hypothalamic explants; (ii) whether acetaldehyde (ACD), its first metabolite formed in the brain by catalase activity, might play a role in EtOH activity. To this aim, rat hypothalamic explants were incubated with: (…
Influence of metformin on GLUT1 gene and protein expression in rat streptozotocindiabetes mellitusmodel
2010
Metformin improves hyperglycaemia via mechanisms which include activation of AMP-activated protein kinase (AMPK). Recent findings indicate that some metabolic actions of metformin occur also by AMPK-independent mechanisms.To study the action of metformin on expression of GLUT1 glucose transporter in rat streptozotocin model of diabetes mellitus.Streptozotocin-induced rats were treated with metformin while monitoring parameters of carbohydrate and lipid metabolism. GLUT1 mRNA and protein expression in kidneys, heart, liver and muscles were studied by means of real time quantitative RT-PCR and immunohistochemistry correspondingly.Metformin treatment decreased glucose concentration, glycated h…