Functional coupling of neurotransmitters with second messengers during cleavage divisions: facts and hypotheses.

: Current data on the role of classical neurotransmitters as multiple and multifunctional regulators of early embryogenesis are reviewed. It is shown that these developmental regulators are coupled with second messengers. Peculiarities of this prenervous coupling emphasized and are used as the basis for discussing the problem of the evolutionary origin of cell regulatory systems.