Effects of (−)-sulpiride and remoxipride on amphetamine-induced locomotor stimulation in rats
| Treatment | Time interval (min) | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| 10 | 20 | ↓ | 30 | 40 | 50 | 60 | 70 | 80 | |
| AMPH | 91 ± 7 | 98 ± 4 | 113 ± 19 | 139 ± 17 | 177 ± 21 | 177 ± 24 | 168 ± 24 | 180 ± 22 | |
| AMPH + RMX | 94 ± 7 | 94 ± 4 | 115 ± 23 | 133 ± 32 | 157 ± 35 | 166 ± 30 | 159 ± 26 | 170 ± 25 | |
| AMPH + SPR | 96 ± 6 | 89 ± 18 | 82 ± 24 | 92 ± 28 | 105 ± 24 | 95 ± 29 | 75 ± 48 | 75 ± 53 | |
Immediately upon d-amphetamine (AMPH) administration (1.0 mg kg−1 s.c.), the animals were placed in the open-field arena and 20 min later (marked by the arrow in the table), (−)-sulpiride (SPR) or remoxipride (RMX) were injected i.c.v. (25 nmol, bilaterally). Controls were given the solvent vehicle at corresponding time points. The table shows mean locomotor activity min−1 ± S.D., expressed as per cent of vehicle-treated controls at the respective time interval. Repeated measurements were made on the same animals (n = 10), which served as their own controls with a changeover design (Li, 1964). Statistical analysis for comparisons between the different treatment conditions was performed by means of an appropriate two-way ANOVA (A × B × S design) (Keppel, 1982). F1,5 = 2.56, n.s. (AMPH vs.AMPH + RMX); F1,5 = 11.90, P < .05 (AMPHvs. AMPH + SPR); F1,7 = 8.48, P < .05 (AMPH + RMX vs. AMPH + SPR).