[Changes in the cytologic and electrophysiologic parameters of rat oocytes in response to prostaglandins F2 alpha and E2]. / Izmenenie tsitologicheskikh i élektrofiziologicheskikh parametrov ootsitov krys pod vliianiem prostaglandinov F-2al'fa i E-2.

Influence of prostaglandins F-2 alpha and E-2 on ovulation character and on the state of the ovulated gametes has been studied in rats at the preovulatory period (the preparations have been injected for 3 days, beginning from the 1st day of early proestrus). Under the effect of prostaglandins the amount of postovulated ova decreases, especially in the animals given prostaglandin E-2. Inhibition of ovulation in these animals is accompanied with an increased part of hyperpolarized ova, appearance of some signs of degeneration in the group of depolarized oocytes and absence of oocytes with polarized membrane at the metaphase I stage. These facts can be interpreted as desynchronization of maturation processes and ova ovulation. Mechanisms of the changes revealed in the ovulatory process and the state of gametes under the prostaglandins effect are discussed.

[Effect of an estrogen-progestin preparation alone and in combination with amizil on the structure and electrophoretic parameters of oocytes and early rat embryos]. / Vliianie estrogen-progestinovogo preparata i ego kombinatsii s amizilom na strukturu i élektrofiziologicheskie parametry ootsitov i rannikh émbrionov krys.

An increasing contraceptive effect at a combined administration of steroid drugs with neurotropic substances--M-cholinolytic benactyzine, makes the problem on the character and mechanism of their action. In the experiments performed in rats, under effect of ethinyl estradiol and norethisteron acetate, and especially at their combination with benactyzine, the first signs of overmaturation are revealed in oocytes situating in the follicular cavity. Therefore, oocytes revealed in the rat fallopian tubes leave behind the development of the control oocytes. The drugs investigated, influencing maturation and ovulation mechanisms of oocytes, produce certain physiological and morphological changes in ovaries of the test rats. This, evidently, defines the mechanism of their elevated contraceptive action. Overmaturation of oocytes in follicles, ovulation at later developmental stages results in increasing amount of degenerative forms of embryos and in disturbance of their development.

[Change in the electrophysiological parameters of human oocytes in the process of maturation outside the body]. / Izmenenie élektrofiziologicheskikh parametrov ootsitov cheloveka v protsesse sozrevaniia vne organizma.

The dynamics of electrophysiological parameters (membrane potential--MP and resistance--R) of the human oocytes was studied during their in vitro maturation. The relationship was established between the changes of electrophysiological parameters and meiotic phases. The average value of MP of diplotene oocytes was 22.0 +/- 0.3 mV and that of R 2.0 +/- 0.5 mO. The membrane depolarization was observed upon the meiotic reinitiation. The MP of diakinesis--metaphase I oocytes amounted to 10.0 +/- 0.3 mV and R to 10.0 +/- 0.5 mO. At metaphase II the temporary membrane repolarisation was noted in some cases which, in some oocytes, was replaced by the increasing hyperpolarisation on the 2--3rd day of cultivation. The input membrane resistance increased on the 2--3rd day of cultivation.

[Change in the electrophysiological parameters of rat oocytes maturing in vivo]. / Izmenenie élektrofiziologicheskikh parametrov ootsitov krys pri sozrevaniia in vivo.

The membrane potential (MP) and input membrane resistance (R) were measured in the immature (1) and mature ovulated (2) rat eggs. The population 1 is homogeneous enough: in 78.3% of all oocytes MP equaled --18 +/- 0.3 mV and R = 3 +/- 0.6 mO; 21.7% of cells had MP = --2 +/- 0.9 MV and R = 3.5 +/- 0.6 mO. The population 2 was divided by the indices under study into 4 groups. The respective values of MP and R in each of 4 groupd 5.5 +/- 0.5 mO, c) --15 +/- 0.6 mV and 7 +/- 1.0 mO, d) --3 +/- 0.4 mV and 9 +/- 0.5 mO. A suggestion is put forward that MP and R of the oocytes change with respect to the maturation stage.