Search results for "Dose–response relationship"

Effects of CGS 10746B on hyperactivity and place preference induced by morphine

2001

The effects of CGS 10746B, a dopamine release inhibitor, on spontaneous locomotor activity, morphine-induced hyperactivity, acquisition of conditioned place paradigm and morphine-induced conditioned place preference (CPP) was evaluated in male mice. In experiment 1, animals treated with CGS 10746B (0.5, 1, 2, 4, 8, 16, 24 and 32 mg/kg), morphine (40 mg/kg) or morphine (40 mg/kg) plus CGS 10746B (0.5, 1, 2, 4, 8, 16, 24 and 32 mg/kg) were placed in an actimeter during a period of 90 min. In experiment 2, animals treated with CGS 10746B (0.5, 1, 3 and 10 mg/kg), morphine (40 mg/kg) or morphine (40 mg/kg) plus CGS 10746B (0.5, 1, 3 and 10 mg/kg) were conditioned following a procedure unbiased …

Effect of inhibiting carnitine biosynthesis on male rat sexual performance.

2008

l-carnitine has a documented role as a cofactor in cellular energy metabolism and fatty acid beta-oxidation pathways and it has also been considered to function in reproductive biology. We investigated whether decreasing concentrations of L-carnitine using an inhibitor of its biosynthesis, mildronate (3-(2,2,2-trimethylhydrazinium)-propionate), would influence the sexual behavior or sperm quality in male rats. Mildronate treatment induced a significant decrease in carnitine concentration and an increase in gamma-butyrobetaine (GBB) concentration in both plasma and testes extracts. However, the expression of carnitine palmitoyltransferase I in testes and testosterone concentration in plasma …

Food intake in lean and obese mice after peripheral administration of glucagon-like peptide 2

2012

We investigated the potential anorectic action of peripherally administered glucagon-like peptide 2 (GLP2) in lean and diet-induced obese (DIO) mice. Mice, fasted for 16 h, were injected i.p. with native GLP2 or [Gly2]GLP2, stable analog of GLP2, before or after GLP2 (3–33), a GLP2 receptor (GLP2R) antagonist, or exendin (9–39), a GLP1R antagonist. Food intake was measured at intervals 1, 2, 4, 8, and 24 h postinjection. In addition, we tested in lean mice the influence of [Gly2]GLP2 on gastric emptying and the effects of GLP1 alone or in combination with [Gly2]GLP2 on food intake. [Gly2]GLP2 dose dependently and significantly inhibited food intake in lean and DIO mice. The reduction of foo…

Uptake and metabolism of choline by rat brain after acute choline administration.

1992

The present study is concerned with the uptake and metabolism of choline by the rat brain. Intraperitoneal administration of choline chloride (4-60 mg/kg) caused a dose-dependent elevation of the plasma choline concentration from 11.8 to up to 165.2 microM within 10 min and the reversal of the negative arteriovenous difference (AVD) of choline across the brain to positive values at plasma choline levels of greater than 23 microM. Net choline release and uptake were linearly dependent on the plasma choline level in the physiological range of 10-50 microM, whereas the CSF choline level was significantly increased only at plasma choline levels of greater than 50 microM. The bolus injection of …

LACTATE, NOT GLUCOSE, UP-REGULATES MITOCHONDRIAL OXYGEN CONSUMPTION BOTHIN SHAM AND LATERAL FLUID PERCUSSED RAT BRAINS

2006

OBJECTIVE: Failure of energy metabolism after traumatic brain injury may be a major factor limiting outcome. Although glucose is the primary metabolic substrate in the healthy brain, the well documented surge in tissue lactate after traumatic brain injury suggests that lactate may provide an energy need that cannot be met by glucose. We hypothesized, therefore, that administration of lactate or the combination of lactate and supraphysiological oxygen may improve mitochondrial oxidative respiration in the brain after rat fluid percussion injury. We measured oxygen consumption (VO2) to determine what effects glucose, lactate, oxygen, and the combination of lactate and oxygen have on mitochond…

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…

Impact of exogenous lactate on survival and radioresponse of carcinoma cells in vitro

2009

Tumour lactate levels have been shown to correlate with high radioresistance in tumour models in vivo. The study aimed to evaluate the impact of pathophysiological extracellular lactate concentrations and acidosis on the in vitro survival and radioresponse of various cancer cell lines.HCT-116, HT29 (colorectal) and FaDu (HNSCC) carcinoma cells were studied. Lactate release rates were determined, and expression of the monocarboxylate transporter MCT1 and its cofactor CD147 were monitored by immunofluorescence and flow cytometry. Colony formation was compared for cells exposed to 20 mM exogenous lactate, acidosis (pH 6.4) and lactate plus acidosis relative to control and dose response curves …

In vivo stimulation of murine haematopoiesis by the antineoplastic agent bryostatin-1

1990

Evidence of a flip-flop phenomenon in acamprosate pharmacokinetics: an in vivo study in rats.

2006

The pharmacokinetics of acamprosate were examined in the rat after oral and intravenous administration in order to detect the possible presence of a flip-flop phenomenon. Rats received 9.3 or 73.3 mg/kg of the drug as an intravenous bolus. The same doses were orally administered via gastric intubation. Plasma samples were taken from the jugular vein for determination of acamprosate concentration by liquid scintillation counting. The drug content was also quantified in urine and faeces. The acamprosate bioavailability was close to 20%, the amount recovered in the faeces being around 80% of the administered dose. The terminal slope of the oral plasma curve was significantly lower than that ob…

Freezing without surrounding cryomedium preserves the endothelium and its function in human internal mammary arteries

2005

Abstract Purpose Cryopreserved human blood vessels may become important tools in bypass surgery. Optimal cryopreservation of an arterial graft should, therefore, preserve both histological and physiological characteristics of smooth muscle and endothelium comparable to the unfrozen artery. Methods Rings from human internal mammary arteries (IMA) were investigated in vitro either unfrozen or after immersion into a cryomedium (RPMI 1640 containing 1.8 M Me2SO and 0.1 M sucrose) and cryostorage with and without surrounding medium. Results In unfrozen IMA, neither contractile responses to noradrenaline (NA) nor endothelium-dependent relaxant responses to acetylcholine (ACH) was modified after e…