Monoaminergic and cholinergic mechanisms of reproduction control in marine bivalve molluscs and echinoderms: a review.

The autoreproduction ability is one of the most important properties of living systems. Evolution of metazoans ensured their reproduction by means of such determinants as sexual cells developing in specialized organs, in gonads. In most marine invertebrates, the gonad produces tens of millions of gametes per reproductive cycle. This reproduction level guarantees the species resistance in the external environment and is provided by the whole organism, though in unfavourable ecological conditions the gonad may become a source of trophic and energy material and it can maintain the viability of organism by means or the mass, often total, lysis of sexual cells. This metabolic interaction of a part (gonad) and the whole (organism) presumes the existence of the strictly determined relations between them, on the one hand, and more or less pronounced autonomy, on the other hand. The isolated organs, including gonads, are capable of fulfilling specific functions for a short period of time by means of local regulation. However, there is no full autonomy between the gonad and the organism: the hierarchical relations set in between them.