Figure 4

Spontaneous horizontal locomotor activity of P11 rats treated (through the maternal circulation) with either 100 mg/kg ketamine HCl (i.p.) or saline on either E18 or E19. Panel A illustrates the entire 30-minute test. In only the initial 5-minute observation period, rats treated with ketamine in utero crossed significantly fewer lines than did the saline control animals. After this initial period of habituation, indicators of horizontal movement declined and group scores converged. Panel B is a minute-by-minute illustration of the first 5 minutes of locomotor activity. In a time-dependent manner, rats treated with ketamine in utero crossed significantly fewer lines than did the control animals. Habituation to the open field is represented by a rapid decline in movement. * = Significantly different from E18/saline group; + = significantly different from E19/saline group. Data were analyzed using a three-way ANOVA [Drug (100 mg/kg ketamine HCl, saline control) X Treatment age (E18, E19) X Time] with time blocks as the repeated time factor and compensation for unequal Ns. If the repeated-measure ANOVA revealed a significant trial effect (indicating a change over time) a two-way ANOVA [Drug (100 mg/kg ketamine HCl, saline control) X Treatment age (E18, E19)] was run to analyze the group differences during a particular trial. Individual group comparisons were accomplished by using the Tukey-Kramer test for Multiple Comparisons. An α = 0.05 was used throughout these analyses. Variance indicators are the Standard Error of the Mean (SEM).