Dietary Mercury Exposure Resulted in Behavioral Differences in Mice Contaminated with Fish-Associated Methylmercury Compared to Methylmercury Chloride Added to Diet
Table 5
Neurotransmitter levels and associated decay products in brain structures of mice fed MeHg- and fish-containing diets.
Brain structures and diets
Days
Neurotransmitters and decay products (pg/mg, mean ± SEM, n = 3)
NE
DA
DOPAC
HVA
5-HT
5-HIAA
Frontal cortex
Control
28
10.8 ± 3.7
2.1 ± 0.8
1.4 ± 0.6
3.5 ± 1.4
4.3 ± 1.8
8.2 ± 3.2
56
11.1 ± 3.2
1.8 ± 0.4
0.25 ± 0.02
1.4 ± 0.2
4.4 ± 2.6
3.6 ± 0.8
MeHga
28
9.4 ± 1.5
2.0 ± 0.6
1.1 ± 0.5
1.7 ± 1.0
2.2 ± 0.6
4.4 ± 0.6
56
5.8 ± 0.7
1.7 ± 0.3
0.36 ± 0.08
0.9 ± 0.6
0.3 ± 0.3
2.6± 0.5
Fishb
28
16.9 ± 4.9
2.2 ± 0.7
0.9 ± 0.2
3.8 ± 1.5
5.8 ± 2.2
6.9 ± 0.7
56
6.8 ± 3.9
2.0 ± 0.2
0.7 ± 0.2
1.1 ± 0.6
2.1 ± 1.2
5.7 ± 2.9
Brainstem
Control
28
15.7 ± 2.8
7.2 ± 1.8
1.1 ± 0.5
2.0 ± 1.0
4.4 ± 0.8
21 ± 7
56
12.3 ± 1.4
3.4 ± 0.4
0.56 ± 0.11
0.8 ± 0.1
4.7 ± 0.1
10 ± 1
MeHg
28
13.2 ± 0.2
3.6 ± 0.3
0.73 ± 0.04
1.04 ± 0.08
4.1 ± 0.3
11 ± 1
56
8.4 ± 4.0
2.3 ± 0.7
0.68 ± 0.19
0.73 ± 0.05
*2.3 ± 0.6
8.9 ± 0.7
Fish
28
14.3 ± 1.7
6.3 ± 1.5
1.2 ± 0.6
1.8 ± 0.8
4.8 ± 0.6
15 ± 3
56
10.2 ± 2.2
3.2 ± 0.8
0.63 ± 0.15
0.8 ± 0.1
3.1 ± 1.0
10 ± 2
Hippocampus
Control
28
18.5 ± 4.6
9.4 ± 3.6
6.6 ± 5.8
5.4 ± 3.6
7.1 ± 2.1
26 ± 7
56
7.9 ± 1.8
2.4 ± 0.7
0.17 ± 0.03
0.7 ± 0.1
5.0 ± 1.2
7.6 ± 1.9
MeHg
28
13.8 ± 2.4
4.6 ± 0.2
2.0 ± 0.8
3.2 ± 1.6
5.4 ± 1.3
12.3 ± 0.4
56
14.4 ± 10.6
12.8 ± 0.8
*2.55 ± 0.06
0.8 ± 0.2
12.4 ± 9.7
49 ± 3
Fish
28
10.5 ± 2.4
4.2 ± 0.4
1.0 ± 0.7
1.8 ± 0.7
6.1 ± 1.9
10.1 ± 1.3
56
12.5 ± 3.3
4.3 ± 1.2
°,§0.85 ± 0.18
1.4 ± 0.2
7.5 ± 2.8
13 ± 3
Striatum
Control
28
6.0 ± 1.3
120 ± 29
68 ± 15
56 ± 18
11.6 ± 4.8
19 ± 7
56
1.3 ± 0.7
79 ± 9
31 ± 5
22.0 ± 1.4
5.7 ± 0.1
5.2 ± 0.3
MeHg
28
4.6 ± 1.5
53 ± 17
60 ± 21
32 ± 10
6.5 ± 1.9
10 ± 2
56
2.8 ± 0.6
65 ± 10
*82 ± 12
*43 ± 5
7.5 ± 3.3
13.4 ± 5.1
Fish
28
5.2 ± 1.6
49 ± 11
23 ± 8
15 ± 4
5.0 ± 1.1
6 ± 1
56
4.9 ± 1.6
61 ± 10
54 ± 14
32 ± 7
5.0 ± 1.0
°8.7 ± 1.0
Cerebellum
Control
28
4.7 ± 1.4
1.2 ± 0.4
0.33 ± 0.11
1.0 ± 0.5
0.4 ± 0.1
5.1 ± 2.4
56
9.0 ± 2.8
1.0 ± 0.3
0.36 ± 0.03
0.81 ± 0.09
2.5 ± 1.0
3.4 ± 0.7
MeHg
28
6.2 ± 0.9
0.96 ± 0.08
0.29 ± 0.16
0.47 ± 0.05
0.38 ± 0.07
2.6 ± 0.1
56
6.3 ± 1.4
0.5 ± 0.2
0.59 ± 0.21
0.5 ± 0.1
1.6 ± 1.0
3.3 ± 1.1
Fish
28
5.1 ± 0.7
0.5 ± 0.2
0.18 ± 0.05
0.44 ± 0.05
0.23 ± 0.06
2.5 ± 0.2
56
3.4 ± 1.7
0.6 ± 0.3
°°0.61 ± 0.03
0.3 ± 0.1
0.16 ± 0.09
1.7 ± 0.9
Midbrain
Control
28
13.8 ± 2.8
6.8 ± 1.8
2.0 ± 0.8
3.3 ± 1.3
3.7 ± 0.8
22 ± 5
56
17.0 ± 2.9
9.0 ± 1.4
2.1 ± 0.2
3.5 ± 0.5
9.5 ± 2.2
23 ± 4
MeHg
28
14.1 ± 2.5
8.6 ± 1.0
2.2 ± 0.4
3.7 ± 0.8
5.6 ± 1.2
19 ± 3
56
11.8 ± 7.3
4.0 ± 1.1
2.5 ± 0.4
3.1 ± 0.4
7.8± 5.6
14.5 ± 0.9
Fish
28
13.1 ± 1.4
7.1 ± 1.2
1.7 ± 0.6
3.2 ± 1.2
5.7 ± 1.0
17± 4
56
10.0 ± 1.3
5.8 ± 1.1
1.8 ± 0.1
3.29 ± 0.05
2.8 ± 1.3
16 ± 1
aMeHg: mice were fed a MeHg-containing diet.
bFish: mice were fed a 4.9% aimara flesh-containing diet. NE: noradrenalin, DA: dopamine, DOPAC: 3,4-dihydroxyphenylacetic acid, HVA: homovanillic acid, 5-HT: 5-hydroxytryptamine or serotonin, 5-HIAA: 5-hydroxyindole-acetic acid. Values appearing in bold characters highlight those significantly different from the control values. Asterisks indicate significant differences in the levels of neurotransmitters or decay products in the brain structures of mice fed the MeHg-containing diet compared to those fed the control diet, as determined with the Students test, *P < 0.05. Circles indicate significant differences in the levels of neurotransmitters or decay products in the brain structures of mice fed the fish-containing diet compared to those fed the control diet, as determined with the Students test, °P < 0.05, and °°P < 0.01. The symbol § indicates significant differences in the levels of neurotransmitters or decay products in the brain structures of mice fed the fish-containing diet compared to those fed the MeHg-containing diet, as determined with the Students test, §P < 0.05.
