Time course and role of extracellular Ca2+ in veratridine-induced glutamate release.

The veratridine-induced release of glutamate in the striatum of anaesthetized rats was studied using regional brain microdialysis to elucidate the role of extracellular Ca2+ and to investigate the exact time course of the glutamate response. In a first series of experiments with Ca(2+)-depletion starting simultaneously with the veratridine pulse no significant differences were found under Ca(2+)-replete and Ca(2+)-free conditions. Strikingly, under both conditions glutamate efflux followed a biphasic time course.

Effects of exogenous factors on the cerebral glutathione in rodents.

Since glutathione is thought to be involved in cerebral functions, changes in the glutathione level imply modulations of the neurotransmission in addition to all the known effects of GSH. It was investigated whether alterations of the cerebral glutathione can be induced by consumption of GSH, by inhibition or stimulation of the synthesis of GSH, or by an inhibition of the re-reduction of the oxidized glutathione. Aminophenazone, propyphenazone, acetaminophen, phenytoin, morphine and nitrofurantoin, known to deplete hepatic GSH, had no effects on cerebral GSH.

Biphasic effect of pyrazolone derivatives on drug-metabolizing enzyme in rat liver.

The pyrazolone derivatives aminophenazone, phenazone, and propyphenazone known as inducers are capable of inhibiting initially monooxygenase-dependent biotransformation steps. In the dose of 1.5 mmol X kg-1 they prolong the hexobarbital narcosis (max.