[The effect of fenoterol (partusisten) on cAMP and cGMP concentrations, acetylcholine esterase and choline acetyltransferase activities in rat placenta].

Several observations indicate a possible role of the placental cholinergic system in the modulation and maintenance of placental function and subsequently fetal growth and development. We have investigated the effect of Partusisten (1 mg/kg p.o.

[Pharmacokinetics of 6-mercaptopurine in rats during postnatal development].

It was shown that 6-MP pharmacokinetics in rats was age-dependent. The distribution processes were mainly influenced by age of animals. 6-MP total distribution volume (VD) increased from 26.

[Chloramphenicol metabolism in the tissues of newborn and adult rabbits].

The in vitro studies on the metabolism of chloramphenicol in the liver, kidney and lung of 5 days old and adult rabbit as well as in the placenta (20-23 day of gestation) have been performed. The metabolites have been identified by thin-layer chromatography technique. Nonmetabolized chloramphenicol and reduction product were estimated by spectrophotometric method.

[Serotonin concentration in the rat fetal brain in experimental intrauterine dystrophy].

The concentration of serotonin (5-hydroxytryptamine, 5-HT) was determined in the brain of fetal rats with experimental intrauterine growth retardation (IUGR). IUGR was induced using the procedure of Wigglesworth. On the 17th day of gestation, the uterine artery supplying one uterine horn was ligated.

[Pharmacokinetics of nitrofurantoin in the bodies of pregnant rats].

The investigation of nitrofurantoin (NTF) pharmacokinetics in pregnant rats was undertaken to estimate its cumulation in the fetus unit. It was found that pharmacokinetics of NTF is dose-dependent in non-pregnant rats. The biological half-life time increased from 0.

[Effect of drugs on cyclic AMP levels in the tissues of animals at different stages of ontogenesis. I. Experimental studies on the effect of adrenomimetic drugs on cyclic AMP concentration in the brain of 7-day-old and adult rats].

The purpose of the investigations was the comparison of the adrenergic receptors excitability in brain of 7-days-old and adult rats after adrenaline and isoprenaline administration. The excitation was evaluated biochemically by measurement of the beta receptor-mediated increase in brain cAMP concentration. There was no significant difference in brain tissue cAMP concentration of 7-days-old and adult rats in physiological conditions.

Experimental and clinical pharmacokinetics of nitrofurantoin in the early period of life.

The investigation of pharmacokinetics showed age-dependent rate of nitrofurantoin elimination in rats. Nitrofurantoin half-life of 0.41 hr in adults was prolonged to 0.

[The effect of biseptol and sodium salicylate administration on the concentration of serotonin and histamine and mono- and diamine oxidase activities in rat placenta].

It is known that two biogenic amines:serotonin and histamine, as well as the enzymes connected with their metabolism (mono- and diamine oxidase), play very important role in human and animal fetal development. We have investigated the effect of Biseptol and sodium salicylate administered to pregnant rats on the concentrations of serotonin and histamine and activities of the above mentioned enzymes in placenta. The obtained results showed that the administration of Biseptol has no influence on the serotonin concentration, whereas the administration of sodium salicylate caused slight increase of serotonin concentration in rat placenta.

[Sulfamethoxazole concentration in the homogenate of the human embryo].

The investigations on the extent of placental drug transfer has conventionally been based on determining drug concentration in cord blood at delivery. There is, however, data that levels in cord blood at delivery may provide misleading information on the extent of drug transfer in utero. It is due to the fact that not every drug reaches the fetus in pharmacologically active form.

[Binding capacity of some drugs to plasma proteins of newborns in comparison with adults (author's transl)].

Comparative studies on binding capacity of some drugs to plasma proteins of newborns and adults were carried out. Plasma from the newborn and adult rabbits as well as human from 4 sources: a) from healthy adults, b) from cord blood, c) from 5 days old newborns, and 6 month old infants were used for the experiments. For methodological reasons in the first part of our studies we have chosen: two sulfonamides - sulfamethazine and sulfamethoxasole, chlorpromazine and sodium salicylate.

[Influence of reserpine on the libration of catecholamines in the brain and heart of rats in ontogenetic development (author's transl)].

The influence of reserpine on the level of noradrenaline and dopamine in the brain, and that of noradrenaline in the heart of rats in various age groups were investigated. It was found that the level of catecholamines in the brain and heart of young rats decreases much more rapidly and to a greater extent than in adult rats.