Table 5. Genotype and sex differences in basal plasma corticosterone levels (A), thermal analgesic thresholds (B), and spontaneous locomotor activity (C) in male and female alcohol naive nPE mice.
(A) Blood was collected 3 hours after lights off and plasma corticosterone levels were assayed by radioimmunoassays; (B) The thermal analgesic threshold test was carried out on a hot plate at 52° C 3 hours after lights off and the time to response (rear paw flutter, rear paw licking or jumping) was measured; and (C) 3 hours after lights off, mice were placed into the appropriate chamber of conditioned place preference apparatus for 30 min, and locomotor activity was assessed as the number of “crossovers”. Genotype difference: *p<0.05 or ***p<0.005 vs. nPE+/+ mice in the same sex; and Sex difference: &p=0.05 or &p<0.01 v. nPE+/+ mice in the same genotype by 2-way ANOVA with Newman-Keuls post-hoc tests.
| A. Plasma corticosterone: Significant effects of genotype [F (1, 13) = 57.6, p<0.000005] and interaction between genotype and sex [F (2, 13) = 5.51, p<0.05]. Post hoc analysis showed that between genotypes, nPE−/− of both sex had higher plasma corticosterone levels than nPE+/+ [p<0.005 for both]. Though overall sex difference was not significant, nPE+/+ females nPE+/+ females had higher plasma corticosterone levels than nPE+/+ males [p=0.05]. | ||||
|---|---|---|---|---|
| 5A | males | females | ||
| Genotype | nPE+/+ (n=4) | nPE−/− (n=5) | nPE+/+ (n=5) | nPE−/− (n=4) |
| Corticosterone, ng/ml | 41 ± 5 | 187 ± 10*** | 84 ± 25 & | 162 ± 13*** |
| B. Hot plate responses: Significant effects of genotype [F (1, 29) = 18.8, p<0.0005] and sex [F (2, 29) = 17.5, p<0.0005]. Post hoc analysis showed that: (1) between genotypes, nPE−/− of both sex had shorter responses than nPE+/+ [p<0.05 for both]; and (2) between sexes, nPE+/+ females had longer hot plate responses than nPE+/+ males [p<0.01]. | ||||
|---|---|---|---|---|
| 5B | males | females | ||
| Genotype | nPE+/+ (n=9) | nPE−/− (n=8) | nPE+/+ (n=9) | nPE−/− (n=7) |
| second | 27 ± 4.1 | 14 ± 1.0* | 38 ± 2.3 && | ± 2.0* |
| C. Locomotor activity | ||||
|---|---|---|---|---|
| 5C | males | females | ||
| Genotype | nPE+/+ (n=8) | nPE−/− (n=8) | nPE+/+ (n=5) | nPE−/− (n=5) |
| Crossover (30 min) | 273 ± 45 | 255 ± 27 | 280 ± 62 | 231 ± 59 |