Drug induced activity in lead-exposed mice.
Three interrelated studies were conducted to examine the locomotor activity of lead-exposed mice. The effects of lead were examined as a function of the dose and duration of exposure. Exposure during the first three weeks occurred via the maternal milk supply. Exposure following weaning was achieved via the water supply. Mice received challenges with various pharmaceutical agents, including d-amphetamine, methylphenidate, apomorphine and phenobarbital. The spontaneous activity prior to injection and the drug-induced activity were monitored. Lead-exposed mice usually displayed spontaneous activity which was indistinguishable from that of the control animals. In only one set of observations did lead exposure result in a modest increase in spontaneous activity. The drug-induced activity varied in a complex manner as a function of the magnitude and duration of the lead exposure. Depressed body weight, which was concurrent with high lead exposure (0.5% Pb(Ac)2) was also a significant parameter affecting both the spontaneous and drug-induced activity.