Figure 1: KOR anti-nociception is lower in female mice.
A) Baseline tail withdrawal thresholds are significantly higher in male C57BL/6J mice, n=10. B) U50 anti-nociception (10mg/kg) is significantly lower in female mice. Left graph is raw data indicating tail withdrawal thresholds from 49oC water. Right graph is transformed data (Percent maximum potential effect, %MPE), n=10. C) U50 dose response curve indicates rightward shift in females, n=6 D) Sex differences exist with another KOR agonist, ethylketocyclazocine (EKC, 1mg/kg, s.c.). Tail withdrawal thresholds from 49oC water were measured before and after injection with EKC E) Transformed data (%MPE) of tail withdrawal thresholds from animals treated with EKC (1mg/kg, s.c.) 10 minutes after drug injection, n=6. F) Females exhibit a rightward shift in the EKC dose response curve, n=6. Data expressed as means +/− SEM.