Chronic cocaine exposure affects stimulus-induced but not spontaneous behavior of the near-term mouse fetus.

Pregnant female mice were injected subcutaneously with a 40-mg/kg dose of cocaine-HCl or physiological saline from day 1 through day 17 of gestation. On day 18 of gestation, dams were surgically prepared to allow the behavior of their fetuses to be observed. Spontaneous motor behavior was unaffected by cocaine exposure. Cocaine exposure potentiated motor responses of the fetuses to ammonia and to control injections of saline into the amniotic sac. Restriction of umbilical blood flow caused a specific stereotyped response in saline-injected fetuses, which is in agreement with studies of other species. This response was markedly potentiated in fetuses exposed to cocaine. The results suggest that the mouse may be a viable model for studies of the neurodevelopmental effects of gestational cocaine exposure and are discussed in relation to current models of the effects of long-term cocaine exposure on brain neurochemistry.