[The effects of dexamethasone and hypoxia on the content of active caspase-3 in the cerebellum and the behavior of neonatal rats].

Synthetic glucocorticoid dexamethasone decreased locomotor activity of neonatal rats 120 h after administration. Behavioral changes were associated with an increase in the content of active caspase-3 in the cerebellum. We found that expression of this apoptotic protease was similar to the control value when dexamethasone action was combined to hypoxic treatment to rats; however, the locomotor activity decreased to the hormone action did not recovered. We found that proapoptotic action of dexamethasone was blocked by hypoxic treatment; however, it was not sufficient for prevention of the effect of hormone on behavior.

[Analysis of mosaic expression of the nptII gene in transgenic tobacco plant lines contrasting in mosaicism].

Differences in the frequency of occurrence of plants with the mosaic phenotype between the Nu5 and Nu6 lines of transgenic tobacco (Nicotiana tabacum) plants remained irrespective of the allelic state of the nptII marker gene. Transition of the nptII gene from the hemizygous state (T3) to the homozygous state (T4) was accompanied by an increase in the frequency of mosaics in both lines. Transition from the homozygous state (T4) into the hemizygous state (F1) resulted in a further increase in the frequency of mosaic plants in the Nu5 line, whereas in the Nu6 line this parameter remained at a high level. Hypermethylation of the pMAS promoter in plants of both lines, as well as differences in the degree of methylation of cytosines in the 5'-region of the coding part of a truncated nptII gene copy between the Nu5 and Nu6 lines, pointed to epigenetic regulation of the mosaic expression of the nptII gene.

[Features of spontaneous locomotor activity in neonatal rats in a novel environment].

Dynamics of spontaneous locomotor activity was investigated in neonatal rats. The increased level of activity and its subsequent decrease in testing were observed already on postnatal day 6 and persisted during the second week of development. These behavioral features were due to simultaneous changes in motility of both front and hind limbs. The analysis of the dynamics of activity revealed two principal components which determined more than 84% of the variability in spontaneous locomotor activity of animals beginning from postnatal day 6. The second component responsible for the increased activity level during the first minute of testing and its subsequent decrease was not correlated with the first component, which determined the basic activity level on the 3-5 min oftesting. This first component was associated with formation of the pyramidal tract.

Negative regulation of caspase-3 expression in the neonatal cerebral cortex by alpha2A-adrenoceptors.

Antisense oligonucleotide to alpha2A-adrenoceptors increased the levels of mRNA (reverse polymerase chain reaction) and protein for a key executioner protease of apoptosis caspase-3 (immunoblotting assay) in the cerebral cortex of newborn rats. The relationship between the observed effect and low expression of alpha2-adrenoceptors was confirmed by the possibility of correcting this phenomenon by clonidine (stimulator of alpha2-adrenoceptors).

Bax and Bcl-XL apoptosis protein mRNA in rat brain stem and cortex during ontogeny.

Bax mRNA level in fetal rat brain stem increases by day 40 of life and then decreases, while level of Bcl-XL mRNA reaches the adult value over one month. Bax mRNA level in the cerebral cortex decreases from day 8 to day 90 of life, while Bcl-XL mRNA level does not change. Judging from Bcl-XL/Bax mRNA ratio, cortical cells exhibit higher readiness to apoptosis than brain stem cells.