Figure 6

Effect of enriched diet and companionship on analgesic effect of sub-optimal dose of morphine in male sickle mice. Male sickle mice housed singly without a companion fed with regular diet (RD/C −) were treated with vehicle, and 3 or 10 mg/Kg morphine sulfate. Another group of male mice fed sickle diet and housed with a female companion were treated with 10 mg/kg morphine sulfate. Hyperalgesia measures for all mice are shown for, mechanical hyperalgesia as PWF in response to 1.0 g von Frey filaments; heat hyperalgesia as PWL in response to a heat stimulus; cold hyperalgesia as PWF per 2 min on a cold plate at 4 °C and deep tissue/musculoskeletal hyperalgesia as grip force exerted by forelimbs. Male HbSS-BERK mice between 8 and 10 months of age were used. Regular diet without companionship, RD/C−, nSS vehicle = 5, nSS 10 mg/kg morphine = 5, nSS 20 mg/kg morphine = 5; sickle diet with companionship, SD/C+, nSS 10 mg/kg morphine = 5; mixed linear models with Tukey’s post-hoc test, *p < 0.05, **p < 0.01, ***p < 0.001 compared to RD/C− with vehicle; ^†p < 0.05, ^††p < 0.01, ^†††p < 0.001 compared to RD/C− with 10 mg/kg morphine. PWF paw withdrawal frequency; PWL paw withdrawal latency.