Early Sea Urchin Embryo as a Model for the Study of Pre-Nervous Functions of Neurotransmitters: New Data

Abstract

The most extensively studied neurotransmitters, such as acetylcholine, catecholamines and indolylalkylamines, are found already in the early, “pre-nerve”-stage embryos of all examined classes of either non-vertebrates or vertebrates (Fig. 1). A comprehensive survey of the available data on the “pre-nerve”-stage neurotransmitters permits the conclusion that the concentration of such compounds changes in a well-regulated fashion at key stages of early embryogenesis. This appears to be true especially at the time of the embryonic cleavage. The common neurotransmitters appear to be functional in “pre-nerve”-stage embryos, and prevention of their function disrupts the course of embryogenesis. This in turn seems to indicate a direct involvement of “pre-nerve” neurotransmitters in the regulatory processes of the early embryogenesis (1–6).