Fig. 1. Time course of the study day in minutes. H/C = heat-capsaicin sensitization. RK = rekindling (40°C for 5 min). M1 = baseline measurements, including the following: (1) quantification of area of secondary hyperalgesia around heat-capsaicin-stimulated skin on the dominant forearm; (2) brief thermal sensitization on the thigh with 45°C for 3 min followed by quantification of area of secondary hyperalgesia; (3) heat pain detection thresholds (HPDT) in normal skin on the upper arm and in the heat-capsaicin-sensitized skin; and (4) long thermal stimulation (45°C for 1 min) in normal skin on the nondominant forearm. M2 = measurements as above (1–4) started 135 min after administration of study drug.