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K Andreas

Publications and source records attributed to K Andreas.

At least 55 records · Page 3Linked to original sources
PubMedDate not supplied

Valproate metabolites in the rat brain--regional distribution in various brain areas.

To investigate the regional distribution of valproic acid (VPA) and 10 of its metabolites in the rat brain, the animals were treated with 300 mg/kg/day VPA i.p. on a 3 times daily dose regimen for 5 days, and the concentrations of the compounds in serum and 15 brain regions were measured. 2-(n-propyl)-(Z)-2-pentenoic acid [(Z)-2-en], a VPA metabolite expected to possess neurotoxic potency in humans, was determined in brain tissue for the first time. The brain/serum concentration ratio of (Z)-2-en was found to be about 14-fold higher than the ratio for its (E)-isomer, thereby demonstrating the influence of the double-bond configuration in the unsaturated metabolites on their ability to penetrate into the central nervous system. The concentrations of VPA and its metabolites in the brain regions were compared to c(hom), the calculated concentration for an assumed homogeneous distribution. The parent drug and its metabolites exhibited individual distribution patterns with varying degrees of inhomogeneity. Elevated metabolite concentrations were found especially in the motorium and the medulla oblongata. Decreased concentrations of VPA and several metabolites were found in the visual cortex.

Animals↗
PubMedDate not supplied

The influence of social isolation on ethanol preference behavior and dopamine release in telencephalon slices in mice.

We examined the relation between the duration of social isolation and alterations in ethanol preference behavior and the dopamine release in telencephalon slices in mice. Ethanol preference developed only after an isolation period of 2 weeks and a further ethanol treatment of 2 weeks. It did not appear after an isolation period of 6 weeks, in mice without ethanol treatment, and in group-housed mice. The dopamine release was lowered in mice isolated for 2 weeks and is normalized in combination with ethanol treatment. The dopamine release inhibition evoked by social isolation of 2 weeks probably reflects a functional state with high sensitivity for induction of an ethanol preference behaviour.

Animals↗