Effects of Nicotine on the Development of an Invertebrate Embryonic System

Abstract

The Cnidarians have traditionally been used as model systems for the study of cell genealogies, cell lineages, cell differentiation, cell-cell interactions, establishment and maintenance of polarity, regeneration, and the factors which control and govern these processes. These animals display a simple architecture. They have a small number of cell lineages and cell types, and they exhibit exceptional morphogenetic plasticity and adaptability. Hydrozoan embryos provide good systems in which to examine the effects of toxic substances on development. These embryos have been used to validate a teratogenic risk assessment bioassay system. Adult lethal and developmentally toxic doses have been determined for a number of chemicals using the hydrozoan system, and the A/D ratios obtained are compatible with those from mammals. Once these dosages are known, one can predict with some certainty those chemicals selectively toxic to the hydrozoan embryo and of probable teratogenic risk to higher animals. The hydrozoan system is being promoted as a system that could effectively predict the teratogenic risk potential of a large number of newly developed or yet untested chemicals in a rapid and cost-effective manner. The research focuses on identifying peak exposure periods (gastrulation), length of test article exposure, and determining endpoints which may be predictive of developmental toxicity.