[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.

[A method of culturing preimplantation mouse embryos].

A modification was proposed for the method of cultivation of preimplantation mouse embryos which does not require mineral oil and strict maintenance of CO2 content of gaseous phase.

Two-component desensitization of nicotinic receptors induced by acetylcholine agonists in Lymnaea stagnalis neurones.

The kinetics of desensitization induced by different agonists of acetylcholine (ACh) as well as the kinetics of recovery from densensitization, have been studied using the voltage-clamp technique in isolated, identified Lymnaea stagnalis neurones. Desensitization follows the sum of two exponentials: one fast and one slow. The time constant of the fast desensitization component (tau Ids) under ACh application is in the range of seconds at room temperature (18-23 degrees C).

[Controlled cell cultivation. IV. The cultivation of isolated neurons of the mollusc, Limnaea stagnalis, in a flow-diffusion chamber].

A possibility of the long-term cultivation of isolated neurons of adult molluscs Limnaea stagnalis in a flow-diffusion chamber has been shown. The construction of the chamber is described by the authors elsewhere; the diagram of the pefusion apparatus has been presented. In the process of cultivation, the nerve cells undergo morphological differentiation to form neuron nets on the glass that involve both individual neurons and their aggregates of 2 to 5 cells.

Completely isolated molluscan neurons. An ultrastructural study.

The neurons of the molluscs Lymnaea and Helix isolated by fermentative digestion followed by mechanical treatment do not differ ultrastructurally from intact ones. These cells have sufficient metabolic reserves and incorporate into RNA 8% of the total radioactive pool, even more than neurons in ganglia under equal conditions. Neuronal damage can occur, mainly during the pipetting, and this is usually expressed in vacuolization of the cytoplasm.