A Symbiotic Relationship between The Blastocystic Ring Trophoectoderm and Uterine Epithelium at The Beginning of Implantation in Rat

Two major fundamental questions are suggested to clarify understanding of cell signalling between trophoblast and uterine epithelium.
1. Is there a pseudosymbiotic recognition reducible to simplify the sum of different implant cell (trophoblast), to receipt cell (uterine epithelium)?
2. Are the recognition signals responsible for these mutually compatible friend cell functions? Are these restricted periods of cellular invasion completely devoid of correlation between the two different types of cells involved in 'compatible interactions'? The studies in pseudosymbiotic systems between implantive tissues, which recognize and control the substance transfer as well as morphogenesis are only different aspects suggested by an interactive phenomenon.
The cytological features of trophoblast cells suggest that the blastocystic ring cells consist of different trophoblastic types according which they have been structurally organized. Probably the functional specialization of trophoblast cells perform: i) supporting, preventing and feeding functions; ii) signalization, polarization, depolarization functions between blastocyst and uterine epithelium; iii) immunological, accepting or rejecting and secretory functions.
According to the ultrastructural evidences, the blastocyst trophoblast cells, showing different features, suggest that structural changes occur in relation to their functions. We believe that the development of these functional properties, during the pre-implantation stage of blastocyst, will be protected as a glaze for new investigations. The trophoblastic cells in different regions of the ring can not only maintain different cytoplasmic contents of small ions and substantial molecules but they can also use the same molecules for different purposes.