Fig. 1.
Local application of 17β-E2 rapidly and dose-dependently enhances bradykinin-induced thermal allodynia in OVX rats. (A) OVX rats received intraplantar injections (50 µl) of 17β-E2 (doses indicated) or vehicle 15 minutes before injection with a subthreshold dose of BK (1 µg). PWL in response to a radiant heat stimulus applied to the ventral surface of the hind paw was measured in duplicate at 5-minute intervals before (baseline) and following each injection. Data are expressed as the change (seconds) from individual preinjection baselines (10 ± 2 seconds) and represent the mean ± S.E.M. of four to six animals per group. **P < 0.01, ***P < 0.001 versus vehicle by two-way analysis of variance (ANOVA) with Bonferroni post-hoc analysis. (B) Dose-response curve for 17β-E2 enhancement of BK-induced thermal allodynia. Data points are from (A) at the time of peak BK response (5 minutes post injection) as a function of 17β-E2 dose. ED50 = 8.85 ng. BL, baseline.