Neuronal cell cultures as toxicologic test systems.

Neuronal cell cultures now represent well-characterized systems with which acute and chronic toxicologic effects of a variety of agents can be evaluated. Extensive synapse formation occurs over a period of days and weeks in these cell cultures and can be assayed semiquantitatively by morphological and electrophysiological means. Detailed morphophysiologic correlations can be made using a technique for injecting an intracellular marker protein, horseradish peroxidase. A variety of neurochemical indices of development, such as transmitter-related enzyme levels, can also be conveniently determined. The developing neuron and its synaptic connections are important objects of investigation since they may be particularly vulnerable to pathogenic materials. Examples of the effects of acute (opiate) and chronic (inhibitory aminoacid) treatments on synaptic function are given.