Chapter 3: Statistical Analyses and Results

1: Y-maze Results

Eachanimal was tested in the Y-maze four times and averages of the four trials were used in

each of the analyses. See Table 2 above for F ratios and Table 3 for significant sex differences, across the three testing periods.

BZP and MAtreated: Percentage of Entries of the Novel Arm of the Y-maze at 30 day wash-out period.

Figure 3: Mean (±S. E. M.) percent of novel entries for control (Saline), BZP (Dose 1 - 5mg/kg; Dose 2 - 10mg/kg; Dose 3 - 20mg/kg) and MA (Dose 1 -0 .5mg/kg; Dose 2 - 1.0mg/kg; Dose 3 - 2.0mg/kg) for PND 31-40, 41-50 and 51-60 male and female rats. † differs significantly (p<.05) from chance expectancy of 50% (one-sample t test). .

Figure 3 illustrates that although the dose effect was not significant for either drug, rats treated with saline during PND31-40 displayed a significant preference for entering the novel arm over the familiar arm and rats treated during PND41-50 with 20 mg/kg BZP or 1.0 mg/kg MA displayed significant preference for entering the familiar rather than novel arm. There was one

sex effect for treatment at PND51-60: female MA-treated rats madesignificantly more entries

BZP and MAtreated: Total Entries of both arms of the Y-maze at 30 day wash-out period.

Figure 4: Mean (±S. E. M.) total entries of both arms for control (Saline), BZP (Dose 1 - 5mg/kg; Dose 2 - 10mg/kg; Dose 3 - 20mg/kg) and MA (Dose 1 - 0.5mg/kg; Dose 2 - 1.0mg/kg; Dose 3 - 2.0mg/kg) for PND 31-40, 41-50 and 51-60 male and female rats. *

significantly different (p<.05) from saline for that particular drug; a,b difference between groups with superscript in common significant (p<.05) for that particular drug.

Figure 4 illustrates that PND31-40 BZP-treatedrats made significantly fewer entries of both

arms of the Y-maze than saline treated rats of the same age. PND 41-50 and PND51-60 BZP-

treated rats made significantly fewerentries of both arms of the Y-maze than saline treated rats

of the same age. For both PND41-50 and PND51-60 BZP-treated rats, there was a significant difference between the lowest and highest doses, indicating that as the BZP dose increased, treated rats became less active. However, in the former case, a significant dose x sex

interaction outlined in Figure 5 showed that the effect applied to female but not male rats. Only the PND51-60 MA-treated rats made significantly fewer entries of both arms of the Y-maze compared to saline-treated rats of the same age. All treated female rats made significantly more total arm entries than similar treated male rats. Overall, the pattern of results suggests that the as dose of BZP increased, regardless of administration age, animals became less mobile. This outcome only typified rats treated with MA during later adolescence.

Drug x sex interaction for PND41-50 BZP treated rats: Total Entries of both arms of the Y-maze at 30 day wash-out period.

Figure 5: Mean (±S. E. M.) total entries of both arms for control (Saline), BZP PND41-50 treated male and female rats. * significantly different (p<.05) from saline for that particular sex. a,b difference between groups with superscript in common significant (p<.05) for that particular drug.

BZP and MAtreated: Percentage of Time spent in the Novel Arm of the Y-maze at 30 day wash-out period.

Figure 6: Mean (±S. E. M.) percent of time spent in the novel arm of the Y-maze for control (Saline), BZP (Dose 1 - 5mg/kg; Dose 2 - 10mg/kg; Dose 3 - 20mg/kg) and MA (Dose 1 - 0.5mg/kg; Dose 2 - 1.0mg/kg; Dose 3 - 2.0mg/kg) for PND 31-40, 41-50 and 51-60 male and female rats. † differs significantly (p<.05) from chance expectancy of 50% (one-sample t test); . * significantly different (p<.05) from saline for that particular drug; a,b difference between groups with superscript in common significant (p<.05) for that particular drug.

Figure 6 shows that, at PND31-40 and PND41-50, saline-treated animals preferred to spend time in the novel arm of the Y-maze over the familiar arm, compared with a mean expectancy of 50%. However, PND31-40 highest MA-treated and PND41-50 highest BZP-treated rats preferred to spend significantly more time in the familiar arms of the Y-maze, compared with a mean expectancy of 50%. Rats treated with 2.0 mg/kg of MA at PND31-40 spent a

significantly less percentage of time in the novel arm, compared to saline- treated rats. At PND41-50, BZP-treated rats spent a significantly less percentage of time in the novel arm of the Y-maze compared with age matched controls. There was one significant sex effect for MA-treated rats at PND51-60; females spent significantly more time in the novel arm of the Y- maze than their male counterparts.

Summary of Y-maze results for 30 day wash-out period.

The Y-maze taps into rats’ innate tendency to explore novel areas (Hughes, 2001; Hughes & Neeson, 2003; Samyai, et al., 2000) and normal animals will enter the novel arm more than the familiar arm, whereas anxious animals will show less of a preference for novelty.

Additionally, the Y maze is a test of short-term spatial memory for brightness change (Gray &

Hughes, 2015). The results showed that there were systematic differencesin measures of

emotionally similar to Aitchison and Hughes (2006) research. That is, as adults, the rats that had been exposed to BZP as adolescents displayed more emotionally than control rats. This

was most evident in the PND41-50 developmental period. Howeverthis may also be attributed

to differences between male and female treated rats, with the female treated rats being more effected by dose increases in BZP compared to male rats. In regards to earlier MA

administration, the results suggest that that administration of MA during the later

developmental period of adolescence (PND51-60) affectsmale rats significantly more than

females, with male rats possibly displaying more anxiety in the Y-maze than females. Overall, the results of adult testing of adolescence BZP and MA administration imply that, 30 days after drug treatment, there are dose-related changes in Y-maze behaviour that could be indicative of changes in anxiety.

In document The behavioural implications of postnatal exposure to benzylpiperazhie and methamphetamine a longitudinal doserelated study in male and female rats (Page 74-78)