Fig. 1. Individual effects of increasing plasma nefopam concentration on the core temperatures triggering sweating (open circles and thin line ), vasoconstriction (filled circles and medium line ), and shivering (open triangles and thick line ) in nine volunteers. Nefopam did not significantly change the sweating or vasoconstriction thresholds; however, the slope of shivering decreased significantly by 16.7 ± 9.5°C ·μg−1· ml, and the shivering threshold decreased by 0.9 ± 0.4°C. All of the thresholds (at a designated skin temperature of 34°C) were calculated from measured skin and core temperatures.