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 | p value | PND-40 | PND-90 | p value | |
| (mean ± SD) | (mean ± SD) | (mean ± SD) | (mean ± SD) | |||
| OFTa | ||||||
| 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 |
| ORTa | ||||||
| (recognition index) | 0.557 ± 0.08 | 0.470 ± 0.14 | 0.154 | 0.3921 ± 0.126 | 0.5632 ± 0.110 | 0.018 |
| MWMb | ||||||
| (% 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 |
| CTAb | ||||||
| (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.
aResults from one-way ANOVA; bResults from two-way ANOVA.