Air Quality Criteria for Lead Volume II of II - (NEPIS)(EPA) - US ...

AX5-29
Subject
Rat, SD, male,
adult
Rat, SD,
PND 120
Rat, SD,
PND 70
Rabbit, Dutch
Belted, male
Monkey,
squirrel
Monkey,
squirrel
Monkey,
cynomolgus
Monkey,
cynomolgus
Monkey,
cynomolgus,
7–8 yr
Monkey,
cynomolgus,
7–8 yr
Exposure
Protocol
Table AX5-3.4 (cont’d). Summary of Key Studies on Neurobehavioral Toxicity
Peak Blood Pb
or [Pb] Used Observed Effects Reference
500 ppm Pb(Ac) 2 28.91 µg/dL Decreases sensitization to the locomotor-stimulating effects of cocaine. Nation et al. (1996)
16 mg Pb(Ac) 2 via gavage
30 days pre-pregnancy to
PND 21
16 mg Pb(Ac) 2 via gavage
30 days pre-pregnancy to
PND 21
Pb(Ac) 2
Mother's blood Pb from
gestation week 5–birth
38.0 µg/dL Self-administering rats prenatally exposed to Pb demonstrate and increased
sensitivity to the relapse phase of cocaine abuse.
Nation et al. (2003)
53.24 µg/dL Increased sensitivity to cocaine in rats perinatally exposed to Pb. Nation et al. (2004)
20, 40, and
80 µg/dL
In utero exposure 21–70 µg/dL
maternal
2 mg/kg/d of Pb(Ac) 2
continuously
50 or 100 µg/kg/d Pb(Ac)2
chronically beginning
at PND 1
Exposed males mated with nonexposed females. Offspring at PND 25
showed Pb-induced effects on exploratory behavior.
21–79 µg/dL Reduced sensitivity to changes in reinforcement contingencies during
behavioral transitions and in steady state.
115 µg/dL at
PND 100
33 µg/dL by
PND 270
PND 100: 15.4
and 25.4
PND 300: 10.9
and 13.1 µg/dL
Pb-induced increase in the number of responses that failed to adequately
displace the bar in the FR schedule and possible subtle motor impairments.
At PND 60: Pb-induced increased mean FR pause times, and, decreased FI
pause times. At 3 yrs of age: Pb-induced increased FI run rate, pause time,
and index of curvature. At both ages, Pb-induced increased variability of
performance.
Delayed alternation at 7–8 yrs of age: Pb-induced impairment of initial
acquisition of tasks; longer delays between alternations resulted in poorer
performance and perseverative behavior, sometimes lasting for hours.
Nelson et al. (1997)
Newland et al.
(1994)
Newland et al.
(1996)
Rice (1988a)
Rice and Karpinski
(1988)
1500 µg/kg/d Pb(Ac)2 36 µg/dL Pb exposure in infancy only impaired spatial discrimination reversal tasks. Rice (1990)
1500 µg/kg/d Pb(Ac) 2
continuously from birth,
during infancy only, or
beginning after infancy
36 µg/dL All Pb-treated groups: same impairments of initial acquisition, indiscriminate
responding, greater impairment with longer delays, and preseverative
responses.
Rice and Gilbert
(1990b)