Fig. 1.

Mechanical and heat responsiveness in GHRHr KO mice at P7.

A: Mechanical withdrawal thresholds to von frey filament stimulation of the hairy hindpaw skin in male mice was not different between WT C57, GHRHr+/− or GHRHr−/− (H_18,22,12 3.6, p < 0.2) mice at P7. B: Female GHRHr+/− and GHRHr−/− mice however displayed reduced mechanical withdrawal thresholds compared to age-matched WT controls (H_{16,26, 26}, 30.0, p < 0.001). C: Combining both sexes shows similar mechanical hypersensitivity in GHRHr+/− and GHRHr−/− mice compared to WT (H_{44, 38, 38} 22.5, p < 0.01). D: Male GHRHr+/− (n = 11) and GHRHr−/− (n = 6) mice showed significantly reduced paw withdrawal latencies to heat stimuli at 40 °C relative to WT (n = 9; F_2,23, 28.4, p < 0.001). E: Female mice showed similar heat hyper-responsiveness as males (GHRHr+/− (n = 8), GHRHr−/− (n = 13), WT (n = 13); F_2,31, 21.6, p < 0.001). F: Overall, GHRHr knockout animals display heat hypersensitivity to WT controls (H_22,19,19, 41.0, p < 0.001). Thermal responsiveness testing showed that the GHRHr KO mice were more hypersensitive than the heterozygotes, but only in males. * p < 0.01 vs WT; ** p < 0.05 vs WT and GHRHr+/−. One-way ANOVA with Holm-sidak post hoc test (parametric) or one-way ANOVA on Ranks’ with Dunn’s post hoc test (non-parametric) as appropriate.