[The action of neurotransmitters and their antagonists on oocyte maturation. The action of serotonin antagonists on the in-vitro maturation of amphibian oocytes].

: Serotonin antagonists (inmecarb hydrochloride and inmecarb methiodide) stimulate in vitro maturation of Bufo viridis and Xenopus laevis oocytes or potentiate the action of progesterone. In contrast to that, serotonin inhibits or blocks oocyte maturation stimulated by progesterone or serotonin antagonists. Sensitivity of B. viridis oocytes to serotonin, its agonists and antagonists is subject to seasonal changes. A maximum sensitivity of intact oocytes is observed in February-March, and that of denuded ones in May-June. We suggest that endogenous serotonin is involved in maintenance of the block of meiosis and in the oocyte maturation control in amphibians.