Although clinically lead poisoning is thought to cause several serious behavioral problems, a causal relationship between lead ingestion and behavioral dysfunction has not been shown. An animal model of lead poisoning was developed in which suckling mice were exposed to lead acetate from birth indirectly through their mothers and then directly after weaning. For the first 60 days, no deaths of offspring occurred due to lead but their growth and development were significantly retarded. Epidemiological evidence exists for the coincidence of lead exposure and hyperactivity syndromes in children. Activity of offspring was measured between 40 and 60 days of age. Treated mice were more than three times as active as agematched controls. Treated and control animals were given drugs used in the treatment and diagnosis of minimal brain dysfunction hyperactivity in children: d- and l-amphetamine, methylphenidate, phenobarbital, and chloral hydrate. Lead-treated hyperactive mice responded paradoxically to all drugs except chloral hydrate: that is, d- and l-amphetamine and methylphenidate suppressed hyperactivity, while phenobarbital increased their levels of motor activity. Chloral hydrate was an effective sedative. Implications of these findings are discussed for the study of the central effects of lead poisoning and for the relationship between lead poisoning and minimal brain dysfunction hyperactivity.
ASJC Scopus subject areas
- Developmental Neuroscience