The use of pharmacological challenges in behavioral toxicology.

Pharmacological challenges offer an opportunity to extend the behavioral observations into biological mechanisms. Behavioral measures may be used to generate hypotheses regarding the mechanisms of toxicity of chemicals, and pharmacological challenges may then be used to test and extend these hypotheses. In using d-amphetamine as a pharmacological probe it was possible to demonstrate postnatal effects of prenatal exposure to methyl mercury (MMC), which were absent without the challenge. This suggests catecholaminergic function to be altered by MMC. Additionally, the use of stressful situations often allows the unmasking of latent damage to the nervous system, which otherwise may remain covered by the functional reserve capacity of the brain.