TY - JOUR
T1 - Performance and exposure indices of rats exposed to low concentrations of lead
AU - Cory-Slechta, Deborah A.
AU - Weiss, Bernard
AU - Cox, Christopher
N1 - Funding Information:
’ This work was supported by Grants ES-01247, ES-01248, ES03054, and ES-03079 from the National Institute of Environmental Health Sciences and under Contract DE-AC02-76EV03490 with the U.S. Department of Energy at the University of Rochester, Department of Radiation Biology and Biophysics, and has been assigned Report No. DOE/EV/3490-2375. These data were presented at the 23rd annual meeting of the Society of Toxicology, Atlanta, Georgia, March 12-16, 1984.
PY - 1985/4
Y1 - 1985/4
N2 - To further characterize the lower end of the function relating lead exposure and biological exposure indices to behavior, male weanling rats were exposed chronically to drinking solutions containing 25 ppm sodium acetate (controls) or 25 ppm lead acetate. Behavioral training began when the animals reached 50 days of age, and performance on a fixed-interval 1-min schedule of food reinforcement was then assessed over 90 experimental sessions (136 days). This exposure produced overall response rate increases over the first 40 sessions that were similar to those observed previously with higher concentrations of lead. Response rates of the two groups tended to merge subsequently. The increased overall response rates in the treated group derived primarily from an increased frequency of shorter interresponse times (IRTs) and increased running rates (calculated without the postreinforcement interval). Blood lead (PbB) and zinc protoporphyrin (ZPP) values were determined following sessions 30, 60, and 90. PbB values of the lead-exposed group averaged 15 to 20 μg/dl throughout the study; ZPP did not differ. The mean brain lead value of the treated group was 0.07 μg Pb/g. Blood-brain ratios (1.38 to 4.06) were substantially greater than those previously observed at higher exposures. These data extend to even lower exposures, and lower blood lead concentrations, the effective concentration for behavioral effects, and further emphasize the importance of the sensitivity of the endpoint in assessing behavioral toxicity.
AB - To further characterize the lower end of the function relating lead exposure and biological exposure indices to behavior, male weanling rats were exposed chronically to drinking solutions containing 25 ppm sodium acetate (controls) or 25 ppm lead acetate. Behavioral training began when the animals reached 50 days of age, and performance on a fixed-interval 1-min schedule of food reinforcement was then assessed over 90 experimental sessions (136 days). This exposure produced overall response rate increases over the first 40 sessions that were similar to those observed previously with higher concentrations of lead. Response rates of the two groups tended to merge subsequently. The increased overall response rates in the treated group derived primarily from an increased frequency of shorter interresponse times (IRTs) and increased running rates (calculated without the postreinforcement interval). Blood lead (PbB) and zinc protoporphyrin (ZPP) values were determined following sessions 30, 60, and 90. PbB values of the lead-exposed group averaged 15 to 20 μg/dl throughout the study; ZPP did not differ. The mean brain lead value of the treated group was 0.07 μg Pb/g. Blood-brain ratios (1.38 to 4.06) were substantially greater than those previously observed at higher exposures. These data extend to even lower exposures, and lower blood lead concentrations, the effective concentration for behavioral effects, and further emphasize the importance of the sensitivity of the endpoint in assessing behavioral toxicity.
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U2 - 10.1016/0041-008X(85)90292-3
DO - 10.1016/0041-008X(85)90292-3
M3 - Article
C2 - 4035681
AN - SCOPUS:0021833888
SN - 0041-008X
VL - 78
SP - 291
EP - 299
JO - Toxicology and Applied Pharmacology
JF - Toxicology and Applied Pharmacology
IS - 2
ER -