Mast cells contribute to hyperalgesia in SCA. (A-D) HbSS-BERK mice were treated with vehicle (Veh), CS, or imatinib (Imat). On day 5, measures of pain were recorded 30 min after the injection of morphine (MS) or phosphate-buffered saline (PBS) as shown in (D). Measures of deep pain (A), mechanical hyperalgesia (B), and thermal sensitivity (C) are shown. BL, baseline obtained before the treatments. *P < .05, **P < .01 versus BL (ANOVA, with Bonferroni). #P < .05, ##P < .01 vs PBS for each corresponding treatment (Student t test). Each value is the mean ± SEM from 8 mice with 3 observations per mouse. (D) Treatment protocol. HbAA-BERK and HbSS-BERK mice were treated with saline, CS, or imatinib sulfate for 5 days. At day 5, a single injection of morphine sulfate or PBS was given and pain behaviors were followed for 240 min. i.p., intraperitoneal; s.c., subcutaneous; red arrow, pain testing. (E-J) Pain-related behaviors of age-matched HbAA BERK, HbSS-BERK, Kit^W/Wv (W/Wv), and HbSS-Kit^W/Wv (HbSS-W/Wv) mice. Each value is the mean ± SEM from 4-6 mice with 3 observations per mouse. *P < .05, **P < .01, ***P < .001 vs HbSS-BERK (ANOVA, with Bonferroni).