Figure 3.

Effects of morphine and 2i on respiratory rate in mice. After acclimation in observation boxes, mice were injected with either saline, morphine 10 mg/kg, or 2i and connected to a throat sensor. Five min later, the recording was started and respiratory rate was measured from 6 min to 45 min post-injection (A). Area under the curve (AUC) was calculated from 6 min to 45 min. Morphine significantly reduced respiratory rate compared to saline (B). Data are expressed as mean ± standard error of the mean (SEM.) (n = 6–8) (**** p < 0.0001). One-way ANOVA followed by Dunnett’s multiple comparison test.