Early Developmental Low-Dose Methylmercury Exposure Alters Learning and Memory in Periadolescent but Not Young Adult Rats
Table 2
The effects of developmental exposure to MeHg on learning and memory in periadolescent and young adult rats.
MeHg 250 μg/kg/day
MeHg 500 μg/kg/day
PND-40
PND-90
value
PND-40
PND-90
value
(mean ± SD)
(mean ± SD)
(mean ± SD)
(mean ± SD)
OFT
Distance (cm)
2512 ± 336.40
2536 ± 301.60
0.868
2118 ± 293.30
2371 ± 301.70
0.073
Rearings (times)
14.10 ± 2.42
13.70 ± 2.16
0.701
12.90 ± 1.97
13.10 ± 1.91
0.820
ORT
(recognition index)
0.557 ± 0.08
0.470 ± 0.14
0.154
0.3921 ± 0.126
0.5632 ± 0.110
0.018
MWM
(% escape latency)
Day 1
100.0 ± 25.59
100.0 ± 19.93
ns
100.0 ± 30.84
100.0 ± 32.46
ns
Day 2
87.44 ± 47.29
79.69 ± 29.36
ns
77.85 ± 33.29
81.98 ± 43.48
ns
Day 3
74.04 ± 51.65
58.96 ± 44.11
ns
70.83 ± 47.24
57.61 ± 37.76
<0.05
Day 4
80.43 ± 55.34
39.62 ± 54.37
<0.01
64.82 ± 47.38
47.58 ± 35.85
<0.01
Day 5
67.10 ± 57.01
28.37 ± 51.32
<0.01
49.55 ± 42.78
30.23 ± 19.77
<0.001
CTA
(aversion index)
Test 1
0.4295 ± 0.09
0.2781 ± 0.09
<0.01
0.4681 ± 0.09
0.2714 ± 0.06
<0.001
Test 2
0.5869 ± 0.10
0.5418 ± 0.11
ns
0.5488 ± 0.06
0.4691 ± 0.11
ns
Test 3
0.6602 ± 0.07
0.6355 ± 0.08
ns
0.6254 ± 0.06
0.6274 ± 0.08
ns
Test 4
0.6844 ± 0.08
0.7161 ± 0.05
ns
0.6435 ± 0.04
0.6859 ± 0.07
ns
Test 5
0.7282 ± 0.05
0.7173 ± 0.13
ns
0.6907 ± 0.06
0.7302 ± 0.05
ns
OFT: open field test; ORT: object recognition test; MWM: Morris water maze; CTA: conditioned taste aversion. Results from one-way ANOVA; Results from two-way ANOVA.
