The rôle of neurohumours in early embryogenesis.

Abstract

In Recent decades the attention of physiologists has been, more than ever, concentrated on the so-called mediators of the nervous system, i.e. low molecular weight physiologically active substances participating in the transmission of nervous impulses through peripheral and central synapses. In this connexion numerous papers have been devoted to the study of the mediators and related enzymes in the embryos of different animal groups. However, the study of mediator systems in embryology has been of a somewhat one-sided character. As a rule, authors have been most interested in the formation of definitive control mechanisms and have therefore worked mainly on late embryos. Their results allow embryologists to use mediator systems as suitable indicators of functional maturity of both nervous structures and innervated organs (Artemov, 1941; Boell & Shen, 1944; Boell, Greenfield & Shen, 1955; Bonichon, 1960; Brachet, 1960; Buznikov, 1960; Chino, 1957; Durante, 1956; Faustini 1955; Hebb, 1956; Kakushkina & Arkhipova, 1940; Mehrotra, 1960; Pepeu & Giarman, 1962; Sawyer, 1943, 1955; Smith, Stacey & Young, 1961; Youngstrom, 1938; and many others).