General Sources of Dopamine As a Potential Morphogenic Factor in the Developing Striatum of Rats.

In the striatum of rats at different stages of development, we determined the content of tyrosine hydroxylase and aromatic L-amino acids decarboxylase using double immunohistochemical labeling and estimated the expression level of their transcripts by real-time PCR. We found that, in different periods of development, there are three sources of dopamine in the striatum of rats: bienzymatic nerve fibers (throughout ontogeny), bienzymatic neurons (appear on day 18 of embryonic development), and monoenzymatic neurons (in adult animals). Dopamine, which is synthesized in the striatal neurons in the prenatal period, may function as a morphogenetic factor.

[Early morphogenesis of ciliated cells in human oral cavity].

Ciliated cells were found in the epithelium of the oral cavity of human embryos and fetuses starting from the seventh week of prenatal development. At the early stages of prenatal development (until the 13th week), cells with cilia cover most of the dorsal surface of the tongue and the soft palate, whereas they are found only near the gland ducts in the circumvallate and foliate lingual papillae after 17 weeks of development. The ultrastructure of the axoneme of cilia corresponds to the structure of motile cilia and is represented by nine microtubule doublets that surround the central pair of microtubule singlets. An immunohistochemical study performed on weeks 10-12 of development identified nerve endings associated with the ciliated cells. Until the 14th week of development, the cytoplasm of ciliated cells is immunopositive for NSE. The spatial distribution of ciliated cells in the tongue epithelium until the 13th week of development is not related to the morphogenesis of lingual papillae, and their role in the human oral cavity during the first trimester of pregnancy is unclear and requires further study.