[The effectiveness of the microsurgical removal of the nuclei in early mouse embryos depending on the time before cleavage division].

The efficiency of microsurgical enucleation of zygote and two-cell mice embryos was found to increase sharply 1-1.5 h before cleavage in "late" embryos, and 5-6 h before cleavage in "early" embryos. In "late" embryos, the share of successful enucleations constitutes 80-90%, and in "early" ones, 10-30%.

[The viability of rat amd mouse embryos in low-temperature preservation].

Embryos of the laboratory rats and mice at the two-cell stage were frozen in different media with 1.5 M DMSO at a rate of 0.5-0.

[Metabolic regulation of neuron functions].

A short analytical review of Soviet and foreign studies devoted to metabolic regulation of neuron functioning is presented. It is shown that the electrical activity of neuron is accompanied by structural changes and an increase in RNA content. It is assumed that these changes are initiated by calcium ions, coming to the neuron during its excitation.

[Electrostimulated cell fusion in cell engineering].

A survey of studies on reconstructions of animal and plant cells which apply a new physical method--electrostimulated fusion, is presented. Effects of different factors of the medium on the efficiency of electrofusion is discussed. A detailed account is given of the authors' studies on zygotes reconstruction by combined methods of microsurgery and electrostimulated cell fusion.

[Nonsurgical embryo transplantation in mice].

Nonsurgical transplantation of the mouse embryos at the blastocyst stage into the uterus was performed using a device of original construction. The use of this device made it possible to exclude the loss of embryos, to reduce the amount of culture medium introduced together with the embryos, to lessen the damage of genital tract and ensured guaranteed "ejection" of embryos into the uterus. The females of the third day of pregnancy were used of recipients.