Ontogenetic development of the monoamine oxidase activity and of the metabolism of biogenic monoamines in rat brain.

The article examines the ontogenetic development of the monoamine oxidase activity and of the metabolism of the dopamine, noradrenaline and serotonin in the brain of newborn, 10-day-, 20-day- and 2-month-old rats. Monoamine oxidase activity is determined using three substrates: tyramine, serotonin and beta-phenylethylamine. Monoamine oxidase A (substrate serotonin) and the total monoamine oxidase activity (substrate tyramine) are found to manifest identical development, their activity increasing quickly after birth, to reach constant values after the 10th day.

Effects of meclofenoxate on the level and turnover of biogenic monoamines in the rat brain.

The level and turnover of biogenic monoamines in some rat brain structures were determined after treatment with meclofenoxate at a dose of 50 mg/kg administered i.p. two times a day (9 a.

Changes in the brain biogenic monoamines of rats, induced by piracetam and aniracetam.

Single oral dose of 600 mg/kg weight piracetam, respectively 50 mg/kg aniracetam, causes essential changes in the level and turnover of dopamine (DA) and serotonin (5-HT) in some rat cerebral structures. When the animals were killed one hour after the administration of the drugs, piracetam significantly increased the DA level in the cerebral cortex and in the striatum, as well as the 5-HT level in the cortex, reducing the 5-HT level in the striatum, brain stem and hypothalamus. At the same time, under the effect of piracetam the DA turnover was accelerated in the cortex and hypothalamus and delayed in the striatum, the noradrenaline turnover was accelerated in the brain stem, the 5-HT turnover was accelerated in the cortex and delayed in the striatum, stem and hypothalamus.

Age-related changes in rat brain dopaminergic receptors.

The number (Bmax) and affinity (Kd) of [3H] spiroperidol binding sites in the cerebral cortex, striatum and hypothalamus of 2-, 10- and 22-month old male Wistar rats (20 rats per group) injected i. p. for 10 days with saline, L-DOPA (250 mg/kg) or haloperidol (1 mg/kg) were determined in the presence of 10(-6) M unlabelled haloperidol.

Changes in rat liver and brain monoamine oxidase activity after acute treatment with some heavy metal salts.

In in vivo and in vitro experiments the effects of some heavy metal salts (Cu, Co, Cd, Pb, Ni, Zn, Hg, As, Bi and Sn) on rat liver and brain mitochondrial monoamine oxidase (MAO) activity was studied using three different substrates (tyramine, 5-hydroxytryptamine (5-HT) and beta-phenylethylamine (2-PEA). It was established that some of the metals (Cu, Cd, Bi) inhibited MAO activity both in vivo and in vitro experiments, others like Ni, Zn, As and Sn inhibited it only in vivo while Hg exerted inhibitory action only in vitro. The in vivo experiments showed significantly higher sensitivity of brain MAO as compared with liver MAO to the inhibitory action of metals.