In Trial 1, each rat pup is placed in the water at the beginning of the entry channel and allowed to swim towards the exit channel, turn right or left, and escape by the ramp at either end of the exit channel. The ramp used to escape remains. The ramp located at the opposite end of the exit channel is removed. Subsequently, the pup is repeatedly placed back into the water in the entry channel and allowed to swim the Single T swim maze in an effort to escape successfully three consecutive times. A successful escape occurs when the rat pup swims the length of the entry channel, enters the exit channel, turns, swims directly to the chosen ramp location, and exits the swim maze.
In the second trial, the exit ramp is moved from the chosen end of the exit channel to the opposite end. Once again the rat pup is repeatedly placed into the Single T swim maze until three successful escapes are accomplished in the new exit ramp location.
Swim Maze Testing in Rat Pups
Number of Swims Until Three Consecutive Escapes
| Dose | Litter | |||||||||||||||||||||
| Sex | (mg/kg) | Trial | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 |
| M | 0 | 1 | 9 | 3 | 9 | 4 | 5 | 6 | 5 | 6 | 4 | 6 | 7 | 9 | 3 | 5 | 6 | 8 | 4 | 5 | 3 | (a) |
| 2 | 12 | 7 | 4 | 4 | 8 | 18 | 6 | 7 | 5 | 6 | 7 | 13 | 8 | 13 | 8 | 4 | 4 | 5 | 4 | (a) | ||
| 3.125 | 1 | 3 | 8 | 4 | 3 | 4 | 3 | 4 | 4 | 7 | 5 | 5 | 10 | 4 | 3 | 6 | 11 | 10 | 6 | 4 | 5 | |
| 2 | 11 | 7 | 6 | 8 | 8 | 6 | 14 | 7 | 7 | 4 | 4 | 5 | 7 | 5 | 4 | 4 | 8 | 8 | 5 | 4 | ||
| 6.25 | 1 | 8 | 9 | 4 | 3 | 12 | 11 | 4 | 4 | 5 | 7 | 8 | 5 | 5 | 5 | 4 | 3 | 5 | 10 | 5 | (a) | |
| 2 | 5 | 10 | 7 | 7 | 7 | 5 | 6 | 7 | 8 | 4 | 8 | 5 | 4 | 9 | 12 | 4 | 13 | 7 | 7 | (a) | ||
| 12.5 | 1 | 8 | 8 | 6 | 6 | 6 | 6 | 3 | 5 | 4 | 4 | 6 | 6 | 12 | 3 | 3 | 8 | 3 | 6 | 9 | (a) | |
| 2 | 8 | 8 | 10 | 8 | 7 | 7 | 6 | 10 | 4 | 6 | 10 | 7 | 6 | 10 | 4 | 6 | 8 | 6 | 5 | (a) | ||
| F | 0 | 1 | 5 | 8 | 9 | 6 | 15 | 6 | 5 | 11 | 4 | 6 | 3 | 6 | 4 | 9 | 3 | 6 | 4 | 6 | 6 | (a) |
| 2 | 8 | 5 | 10 | 19 | 7 | 7 | 6 | 7 | 4 | 9 | 4 | 9 | 9 | 5 | 6 | 5 | 11 | 6 | 5 | (a) | ||
| 3.125 | 1 | 6 | 5 | 4 | 4 | 8 | 3 | 4 | 11 | 3 | 7 | 7 | 4 | 4 | 6 | 9 | 3 | 6 | 5 | 6 | 6 | |
| 2 | 8 | 6 | 5 | 9 | 8 | 7 | 6 | 14 | 7 | 8 | 11 | 10 | 8 | 9 | 15 | 11 | 4 | 7 | 6 | 6 | ||
| 6.25 | 1 | 3 | 3 | 3 | 3 | 10 | 4 | 4 | 4 | 3 | 3 | 7 | 5 | 3 | 5 | 3 | 7 | 6 | 3 | 6 | (a) | |
| 2 | 15 | 7 | 6 | 8 | 4 | 5 | 11 | 5 | 6 | 8 | 47 | 9 | 6 | 7 | 7 | 6 | 4 | 8 | 4 | (a) | ||
| 12.5 | 1 | 5 | 4 | 7 | 3 | 5 | 3 | 8 | 10 | 4 | 4 | 5 | 3 | 5 | 8 | 4 | 12 | 6 | 4 | 5 | (a) | |
| 2 | 9 | 4 | 5 | 6 | 7 | 10 | 4 | 4 | 9 | 5 | 7 | 5 | 6 | 14 | 4 | 4 | 3 | 9 | 5 | (a) | ||
(a) N=19 litters only