Figure 1. Hindpaw inflammation decreases wheel running in male and female rats.
CFA or saline was injected into the right hindpaw of male (Top) and female (Bottom) rats. Injection of saline caused a transient decrease in running that returned to baseline levels within 3 hrs. In contrast, injection of CFA caused a complete and prolonged inhibition of wheel running in both male and female rats. Sample sizes ranged from 49 – 68 rats in each condition. The sample sizes are large because these rats were subsequently tested with different opioid doses.