xvEPA
United States
Environmental Protection
Agency
Health Effects Research
Laboratory
Research Triangle Park NC 27711
Research and Development
EPA-600/S1-81-013 Mar 1981
Project Summary
Chronic Toxicity of Lead and
Cadmium: II. Changes in the
Central Nervous System of the
Fi Generation of Rats After
Chronic Intoxication With
Lead and Cadmium
Z. S. Herman, K. Kmieciak-Kolada, R. Szkilnik, R. Brus, J. J. Jonek, K. Ludyga,
R. Winter, J. Bodztony, B. Hebrowska, K. Kaminski, D. Piskorska, and
J. Wyrebowska
Lead (Pb) and cadmium (Cd) are
hazardous trace elements found in the
present environment of man. Taking
into account possible individual and
synergistic effects of chronic exposure
to Pb and/or Cd, we have previously
studied the effect on the central ner-
vous system in rats chronically expos-
ed to drinking water containing Pb
and/or Cd in trace amounts. PreviousT
ly, we have shown that a brief Pb
and/or Cd exposure affects the subtle
functions of the nervous system. In
this paper we present the changes in
behavior and biogenic amine concen-
trations in discrete brain areas of rats
from the Fi generation.
Forty-day old male and female rats
received one of the following treat-
ments in their drinking water: Group I
(control), 0.005 M acetate buffered
drinking water; Group II, 5 ppm Pb;
Group III, 50 ppm Pb; Group IV, 0.1
ppm Cd; Group V, 5 ppm Pb and 0.1
ppm Cd; Group VI, 50 ppm Pb and 5
ppm Cd. Pb and Cd acetate salts were
dissolved in drinking water buffered to
pH 7 with an 0.005 M acetate buffer.
Animals were exposed for 40 days and
pregnant females continued on these
regimens throughout gestation and
lactation. Rats born from these animals
(Fi generation) were similarly exposed
for 40 days beginning 20 days after
birth. Each control and experimental
group of animals of the F, generation
consisted of 1O rats. All evaluations
described were made at 30, 60 and 90
days of age.
This Project Summary was develop-
ed by Health Effects Research Labora-
tory, Research Triangle Park, NC, to
announce key findings of the research
project which is fully documented in a
separate report of the same title (see
Project Report ordering information at
back).
Behavior
Locomotor activity from all treatment
groups during Pb/Cd exposure is report-
ed as a percentage of control values
(Table 1). Increased diurnal and noctur-
nal locomotor activity was evident in 30-
day old rats treated with 5 ppm Pb, while
at 60 and 90 days a decrease in these
activities was observed. Fifty ppm Pb
treatment increased diurnal locomotor
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Table 1. Locomotor Activity Changes (Percent of Control)* Following Exposure to
Lead and/or Cadmium
Control
Measurement
Time
Day
Night
Age
/Days}
30
60
90
30
60
90
{Counts/
12 hr±
SD.J
929 ±11 8
1096 ±105
950 ± 89
1690±182
1708±175
1670 ±152
5 ppm
Pb
181"
87
80
280"
44*
65C
50 ppm
Pb
142
161
120
90
138
62
b
b
b
c
0 1 ppm
Cd
163
68
73
186
116
95
b
c
c
b
5 ppm
Cd
84
107
124C
183*
85
112
5 ppm Pb
+ 01 ppm
Cd
132C
82
63C
161*
88
54*
50 ppm
Pb + 5
ppm Cd
87
61*
99
132C
48*
91
a - n = 10 for all groups
* -p<0.01
c -p<0.05
activity in 30-, 60-, and 90-day old rats.
In 90-day old rats there was an evident
decrease in nocturnal activity. Cd (0.1
ppm) also increased locomotor activity
of 30-day old rats, while the diurnal
activity in 60- and 90-day old animals
decreased. Changes in locomotor activity
after Cd exposure (5 ppm) were seen as
an increase of nocturnal activity in 30-
day old rats. After simultaneous treat-
ment with lower doses of Pb and Cd, an
increase in activity of 30-day old animals
was observed and a decrease in diurnal
and nocturnal activity of 90-day old rats
was observed. Higher doses of Pb and
Cd in 60-day old rats produced a depres-
sion in locomotor activity.
Biogenic Amines In Discrete
Areas Of Brain
Regional brain NA and DAconcentra-
tions are presented in Tables 2 and 3.
Overall, the intoxication by Pb caused a
decrease in NA content in the examined
brain areas while Cd caused an increase.
Pb and Cd applied concomitantly in
lower doses caused an increase in NA in
30- and 90-day old animals. Higher
doses usually caused a decrease of NA
in 30- and 60-day old rats and an
increase in 90-day old animals.
After 5 ppm Pb, DA level in the
striatum increased in 30- and 60-day
animals. Exposure to 50 ppm Pb de-
creased striatal DA in 30- and 60-day
old rats and increased DA in 90-day old
rats. Cd (0.1 ppm) increased striatal DA
concentrations in 30-day old rats and
decreased it in 60- and 90-day old ani-
mals. Cd (5 ppm) increased DA in 60-day
old rats. Combined Pb and Cd exposure
to lower concentrations significantly in-
creased DA in 30-day old rats, while
exposure to 50 ppm Pb and 5 ppm Cd
increased striatal DA in 30- and 60-day,
but not in 90-day old rats.
In general, treatment with 5 ppm Pb
decreased 5-HT and increased 5-HIAA
in specific areas of the brain (Tables 4
and 5). Thirty-day old rats exposed to 50
ppm Pb showed an increase in 5-HT and
5-HIAA in the brain stem while a de-
crease in 5-HT was observed in the
limbic system. In 60- and 90-day old
rats, exposed to 50 ppm Pb, 5-HT and 5-
HIAA levels were increased in specific
areas of the brain.
Increased striatal 5-HIAA was noted
in animals receiving 0.1 ppm Cd. In 60-
day old rats, a decrease in 5-HT in the
hypothalamus, limbic system, and brain
stem were seen. Decreased 5-HIAA in
the hypothalamus and striatum was
also observed in these 60-day old
animals. In 90-day old rats, an increase
of striatal 5-HT and a decrease of 5-
HIAA in the hypothalamus, limbic sys-
tem, and striatum were seen.
An increase in brain stem 5-HTand 5-
HIAA was observed in 30-day old rats
treated with 5 ppm Cd. In 60-day old
rats, the level of 5-HT decreased in the
Table 2. Noreadrenalin (NA) Changes (Percent of Control^ Following Chronic
Exposure to Lead and/or Cadmium
Brain Area
Hypothalamus
Rons plus
Medulla
Limbic
System
Striatum
Age
(Days)
30
60
90
30
60
90
30
60
90
30
60
90
Control N A
Concentra-
tion (fjg/g ±
SE1
2.28 ±0.08
2. 40 ±0.07
2. 30 ±0.06
0.69 ±0.02
0.69 ±0.02
0.67 ±0.01
0.61 ±0.03
0.59 ±0.01
0.55 ±0.01
0.32 ±0.04
0.32 ±0.04
0.31 ±0.01
5 ppm
Pb
96
141C
95
101
132*
120*
60*
135*
136*
135*
137*
135*
50 ppm
Pb
54*
56*
114
96
99
46°
50°
54*
110
105
113
80C
0. 1 ppm
Cd
105
129*
103
89
109
109
80°
126C
103
85C
71*
107
5 ppm
Cd
77C
115C
103
90
112
88
79°
113
96
84C
93
104
5 ppm Pb
+ 0.1 ppm
Cd
120°
92
98
89
95
720°
71*
94
122C
162*
98
131*
50 ppm
Pb + 5
ppm Cd
90
89
98
74*
95
103*
103
64°
125C
84C
100
140C
* - n = 8 for all groups
* - p <0.01
c -p<0.05
Table 3. Dopamine (DA) Changes (Percent of Control}* Following Chronic
Exposure to Lead and/or Cadmium
Brain Area
Striatum
Age
(Days)
30
60
90
Control NA
Concentra-
tion ffig/g ±
S.E.I
5.58 ±0.33
5.66 ±0.20
5. 14 ±0.20
5 ppm
Pb
298*
120C
118
50 ppm
Pb
70
62
223
b
b
0. 1 ppm
Cd
402
70
72
b
b
b
5 ppm
Cd
93
122*
85C
5 ppm Pb
+ 0.1 ppm
Cd
265*
90
87
SO ppm
Pb + 5
ppm Cd
133*
121C
89
* - n — 8 for all groups
* - p <0.01
c - p <0.05
-------
Table 4.
5-Hydroxytryptamine (5-HT) Changes (Percent of Control)* Following
Chronic Exposure to Lead and/or Cadmium
Control 5-HT
Age Concentration 5 ppm 50 ppm 0 1 ppm 5 ppm 5 ppm Pb + 50 ppm Pb
IDaysl
/fjg/g±SE)
Pb
Cd
Cd 0 t ppm Cd +5 ppm Cd
Hypothalamus
Rons plus
Medulla
Limbic
System
Striatum
30
60
90
30
60
90
30
60
90
30
60
90
2.1
2.0
2.0
0.98
0.96
0.91
0.95
0.93
0.95
0.92
0,98
0.93
±
±
±
±
±
±
±
±
±
±
±
±
0.1
0.1
0.1
0.04
0.1
0.03
0.04
0.06
0.05
0.02
0.08
0.10
93
97
92
125C
59C
86
86
70*
142*
98
51*
107
90
103
138"
155C
4T
40C
70C
75C
131*
101
73C
37*
95
82C
95
108
85
109
104
84C
102
110
87
133*
104
102
101
155"
81C
97
96
88C
114
97
106
100
113
92
89
112
185*
120C
767*
128*
134*
88C
115C
140*
114
104
107
119C
76C
76C
100
81C
69*
130*
119C
67*
8 - n = 8 for each group
* -p<0.01
c -p<0.05
Table 5. 5-Hydroxyindoleacetic Acid (5-HIAA) Changes (Percent of Control)"'
Following Chronic Exposure to Lead and/or Cadmium
Brain Area
Hypothalamus
Rons plus
Medulla
Limbic
System
Striatum
Age
(Days/
30
60
90
30
60
90
30
60
90
30
60
90
Control 5-HIAA
Concentration
(ug/g±SE!
2.5
2.5
2.3
0.63
0.61
0.65
0.62
0.63
0.59
0.95
0.09
1.0
±
±
±
±
±
±
±
±
±
±
±
±
0.2
0.1
0.1
0.03
0.05
0.02
0.04
0.04
0.03
0.03
0.05
0.1
Sppm
Pb
97
72*
70*
141*
165*
106
91
136*
101
149*
125*
104
SO ppm
Pb
96
97
86
170*
214*
110
97
127*
88
174*
98
152*
0 1 ppm
Cd
92
76°
43*
115C
105
129*
80C
107
57*
237*
69*
65*
5 ppm
Cd
54*
119C
89
159*
145*
93
151*
130*
117C
98
97
126*
5 ppm Pb +
0 7 ppm Cd
102
88
77C
73*
143*
173*
50*
115C
119C
95
103
101
50 ppm Pb
+ 5 ppm Cd
76
c
96
74
138
183
97
161
127
93
105
b
b
b
b
b
83°
77
c
8 - n = 8 for each group
* -p<0.01
c -p<0.05
Table 6. Specific Biochemical Changes (Percent of Control)" Following Exposure
to Lead and/or Cadmium
ALA-
dehydratase
blood
Acetyl-
cholinesterase
brain
Monoamine
oxidase
brain
Free
Erythrocyte
Porphyrins
Age
IDaysl
30
60
90
30
60
90
30
60
90
30
60
90
Control
Mean ±S E
121
48
49
5.8
6.7
6.0
64
69
60
183
103
120
±
±
±
±
±
±
±
±
±
±
±
±
25
18
17
1.3
0.5
1.1
15
19
15
58
23
15
5 ppm
Pb
32*
52*
42*
146*
100
62*
330*
50*
50*
327*
448*
339*
50 ppm
Pb
15
73
71
70
100
100
25
64
72
391
412
224
b
b
b
b
b
b
b
b
b
b
0 1 ppm
Cd
—
—
752"
151
180*
160*
158*
—
—
5 ppm
ca
.
—
—
— .
148*
180*
100
158*
316*
—
—
5 ppm Pb +
0 / ppm Cd
21*
25*
50*
81°
42*
100
61*
58*
63*
247*
473*
360*
50 ppm Pb
+ 5 ppm Cd
90
46*
63*
55*
80C
72*
100*
170*
176*
290*
110
318*
- n = 8 for each group
* -p<0.01
c -p<0.05
brain stem and limbic system while the
5-HIAA level increased in the brain
stem and limbic system. Increased 5-
HIAA levels were found in the limbic
system and Striatum of 90-day old ani-
mals.
Effects of the combined Pb-Cd expo-
sures were primarily synergistic or
protective and were not related to age or
dose.
Biochemical Changes
ALA-dehydratase activity in the blood
was significantly decreased and free
erythrocyte porphyrins were signifi-
cantly increased in Pb-treated rats
(Table 6). AChE and MAO activity in
whole brain were variously affected in
rats intoxicated by Cd and/or PB (Table
6). LDH activity and AlPh activity were
not significantly changed in any exam-
ined group of animals.
Conclusion
Our behavioral studies have shown
that both Pb and Cd alter locomotor
activity. In control animals, age had no
effect on either diurnal or nocturnal
activity. In animals treated with Pb or Cd
singly there was no pattern to the
alterations in locomotor activity with
dose or age at testing. When treated
with the Pb-Cd combination, 30-day
activity was generally elevated; whereas,
60- and 90-day activity was depressed.
These CNS mediated activity changes
seen in laboratory animals are similarto
the clinical syndrome of Pb intoxication
in children.
> US GOVERNMENT PRINTING OFFICE 1961-757-012/7034
-------
Z 5. Herman. K. Kmieciak-Kolada, R. Szkilnik, R. Brus, J.J. Jonek, K. Ludyga, R.
Winter, J. Bodziony, B. Hebrowska. K. Kaminski, D. Piskorska, and J.
Wyrebowska are with the Departments of Pharmacology, Biochemistry,
Cytlogy and Histology, Central Animal Farm of Silesian Medical Academy,
Katawice, Poland.
John Laskey is the EPA Project Officer (see below).
The complete report, entitled "Chronic Toxicity of Lead and Cadmium:
II. Changes in the Central Nervous System of the Fi Generation of Rats After
Chronic Intoxication With Lead and Cadmium," (Order No. PB 81-150 989;
Cost: $5.00, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, v'A 221'61
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Health Effects Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Pottage and
Environmental
Protection
Agency
EPA 335
Official Business
Penalty for Private Use $300
00003?*
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