Table 2.

ED50 values (and 95% confidence limits) for DAMGO microinjected in the RVM of rats that received an intraplantar injection of saline or CFA

Intraplantar treatment intervalIntraplantar salineIntraplantar CFA
IpsilateralContralateralIpsilateralContralateral
4 hr10.713.60.655.5**
(6.7–20.1)(8.2–27.8)(0.4–1.0)(3.3–8.5)
4 d16.223.70.212-a9.2*
(10.1–32.0)(12.7–72.6)(0.09–0.4)(5.1–18.4)
2 weeks17.618.50.022-a1.9**2-a
(10.3–37.6)(10.1–46.4)(0.009–0.04)(1.1–3.1)
  • ED50 values are expressed as nanograms. Asterisks indicate ED50 values for the contralateral, uninflamed hindpaw of CFA-treated rats that differ from that of the contralateral, noninflamed hindpaw of saline-treated rats: *p < 0.05, **p < 0.01.

  • F2-a Indicates ED50 values that significantly differ from the previous time point, p < 0.01.