Prenatal diazepam: chronic anxiety and deficits in brain receptors in mature rat progeny.

Pregnant rats were treated with daily doses (5.0 to 7.5 mg/kg, SC) of the benzodiazepine (BDZ) receptor agonist, diazepam (DZ) between day 15 through day 20 of gestation, i.e., during ontogenesis of BDZ receptors in an attempt to alter their development. In the radial arm maze, 6 months old rat progeny showed behavioral anomalies and deficient exploratory behavior. One plausible interpretation of their poor performance is a deficit in short-term spatial "working memory." However, a more detailed evaluation of their behavior suggests a chronic state of hyperarousal/anxiety and thus, poor focus of attention on the task at hand. In addition, the number of brain BDZ receptors in the thalamus, at the age of one year, was significantly reduced. Hence, prenatal exposure to DZ has enduring and detrimental effects on brain function.