Effects of acute treatment with dopaminergic drugs on open field behavior of adult monkeys treated with lead during the first year postpartum.
A pharmacological challenge of nonhuman primate open field behavior, similar to that which previously assessed the cholinergic system (10), was used here to measure potential lead-induced alterations in the dopaminergic system. Monkeys that had been treated with lead during the first year postpartum were assessed at 7 years of age in the open field after acute intramuscular injection of apomorphine (0.0-0.3 mg/kg) or haloperidol (0.0-30 micrograms/kg). Duration of environmental exploration indicated a possible greater responsivity to 0.2 mg/kg apomorphine in the lead-treated monkeys; however, in all other behaviors, lead-treated monkeys responded to both drugs similarly to controls. Regardless of lead treatment, apomorphine administration decreased duration of inactivity and increased environmental exploration; the latter possibly included an increase in stereotypical behavior that might have been recorded as environmental exploration. Haloperidol had no significant effects on open field behavior over the dose range tested. Open field behavioral alterations previously reported for these monkeys at 4-6 years of age were no longer strongly exhibited by the lead-treated monkeys in any portion of the current study. Latency to enter the open field was marginally increased in the lead-treated group but levels of environmental exploration were comparable to controls. These results indicate an attenuation of lead-related effects with maturity and/or familiarity with the open field.
Ferguson
S A
SA
Division of Reproductive & Developmental Toxicology, National Center for Toxicological Research, Jefferson, AR 72079, USA.
Felipa
H N
HN
Bowman
R E
RE
D000704:Analysis of Variance; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology*; D001522:Behavior, Animal / Q000187:drug effects*; D018491:Dopamine Agonists / Q000494:pharmacology*; D018492:Dopamine Antagonists / Q000494:pharmacology*; D005106:Exploratory Behavior / Q000187:drug effects; D005260:Female; D006220:Haloperidol / Q000494:pharmacology*; D007854:Lead / Q000633:toxicity*; D008253:Macaca mulatta; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D011930:Reaction Time / Q000187:drug effects; D012016:Reference Values; D018709:Statistics, Nonparametric
D018491:Dopamine Agonists; D018492:Dopamine Antagonists; D007854:Lead; D006220:Haloperidol; D001058:Apomorphine