extremely significantP < 0.0001
Interestingly, our two-way ANOVA revealed that this increment is only owing to the extremely significant effect of tramadol treatment ( F [1, 30] = 21.34, P < 0.0001), since no statistically significant effect was seen for the time of tramadol administration ( F [2, 30] = 1.926, P=0.1633) or for the time-treatment interaction ( F [2, 30] = 1.557, P = 0.2274).