APPROPRIATE END-POINTS FOR THE CHARACTERIZATION OF BEHAVIORAL-CHANGESIN DEVELOPMENTAL TOXICOLOGY

The present paper is devoted to second- and higher-tier test methods f or the characterization of behavioral changes produced in rodents by e xposure to noxious agents during development. The paper analyzes a ser ies of end points that are informative about specific processes and un derlying regulatory mechanisms but require greater technical sophistic ation and larger investments than first-tier end points. This applies to ultrasonic emissions in successive postnatal periods; to mother-pup interactions, including appropriate cross-fostering controls, to soci al (including sexual) interaction tests from the infantile to the youn g adult stage; and to a variety of conditioning and learning tests usi ng both positive and negative reinforcement.