Fig. 5. Antinociceptive effects (% maximum possible effect [MPE]) of intrathecal [i.t.] FE 200665. (A ) Dose–response relation and (B ) antagonism by naloxone methiodide (NLXM; administered subcutaneously and intrathecally). P < 0.05, analysis of variance (linear regression). s.c. = subcutaneous; i.pl. = intraplantar.