Figure 5.

Paw withdrawal thresholds on the von Frey mechanical allodynia measure for males (A) and females (B) shows post-weaning, adolescent, and adult male rats in the control, handle, and needle prick groups. (all N’s identical to that of Figure 4). Paw withdrawal latencies on the Hargreaves thermal hyperalgesia measure for acute pain male (C) and female (D) rats during post-weaning, adolescence, and adulthood. * represents a statistically significant difference from control. # represents a statistically significant difference between age groups when collapsed across neonatal pain condition. These data indicate that both male and female post-weaning rats that received needle pricks or handling showed a mechanical hypersensitivity the dissipated with age, and that older male rats are hypersensitive to thermal stimuli irrespective of neonatal pain condition.