[The effect of a serotonin deficiency on mammalian embryonic development]

Administration of p-chlorophenylalanine to mouse females leading to a decreased level of endogenous serotonin during the early periods of pregnancy leads either to the absence of cytokinesis at the stage of zygote or to a sharp reduction of the cleavage rate in embryos up to its complete arrest. Formation of the blastocyst is impaired, although cavitation may take place at the same time as in the control. In the latter case, the blastocysts consist of a small number of large blastomeres, and the separation into trophoblast and inner cell mass is characteristically indistinct. Decreased level of endogenous serotonin at early postimplantation stages, i.e., during active organogenesis, leads to abnormalities in the development of brain, eyes, jaws, abnormalities of the brain vessels and vascular system of other body regions, which appear as numerous hematomas and hemostasis in vessels.