Table 2.
Total Exploration Time (sec)
| SEM | ||||||
|---|---|---|---|---|---|---|
| Experiment | Familiarization Phase | |||||
| SS | SM | NS | NM(1) | NM(2) | NM(3) | |
| PND 40-96 | 23.7 | 25.1 | 37.6 | 26.5 | ||
| (Figure 1A) | (2.7) | (2.6) | (4.2) | (4.0) | ||
| PND 61-100 | 30.5 | 28.2 | 40.3 | 30.9 | ||
| (Figure 1B) | (8.9) | (4.3) | (3.7) | (3.7) | ||
| PND 40-61 | 37.1 | 32.7 | 38.9 | 39.9 | ||
| (Figure 1C) | (5.7) | (3.8) | (7.6) | (4.2) | ||
| PND 40-88/89/96 | 37.7 | 26.3 | 35.1 | 31.2 | 30.1 | 29.9 |
| (Figure 2A) | (4.1) | (4.5) | (5.8) | (3.9) | (4.8) | (4.1) |
| PND 89-96 | 45.9 | 39.0 | 49.1 | 42.7 | ||
| (Figure 2B) | (5.3) | (4.3) | (8.5) | (4.4) | ||
| Experiment | NOR Phase | |||||
|---|---|---|---|---|---|---|
| SS | SM | NS | NM(1) | NM(2) | NM(3) | |
| PND 40-96 | 29.0 | 26.0 | 35.7 | 23.2 | ||
| (Figure 1A) | (5.7) | (3.1) | (5.8) | (4.1) | ||
| PND 61-100 | 17.8 | 23.5 | 33.0 | 21.3 | ||
| (Figure 1B) | (4.5) | (5.0) | (6.0) | (4.8) | ||
| PND 40-61 | 36.4 | 34.8 | 40.6 | 24.7 | ||
| (Figure 1C) | (4.6) | (5.6) | (5.3) | (2.2) | ||
| PND 40-88/89/96 | 23.5 | 23.6 | 27.0 | 20.5 | 16.9 | 27.6 |
| (Figure 2A) | (3.6) | (4.8) | (4.4) | (7.5) | (2.8) | (6.1) |
| PND 89-96 | 29.2 | 33.5 | 34.6 | 18.3* | ||
| (Figure 2B) | (4.8) | (5.0) | (6.1) | (1.5) | ||
Rats received oral NIC (N) via drinking water or tap water (S) from PND40-96, PND61-100, PND40-61, PND40-88 (NM(3)) 89 (NM(2)), or 96 (NM(1)) or from PND89-96 and either saline (S) or METH (M) injections at doses and ages delineated in Figures 1 and 2 insets and Methods. Object familiarization (familiarization phase) and recognition (NOR phase) were performed 6 d after saline or METH injections as described in methods. Data are expressed as mean values ± SEM.
Abbreviations: M = methamphetamine; N = nicotine; NM = nicotine/methamphetamine; NOR = novel object recognition; NS = nicotine/saline; PND = postnatal day; SM = tap water/methamphetamine; SS = tap water/saline.