Fig. 6.

Heart rate (open squares), body temperature (open triangles), and overall activity (open diamonds) prior to and 1, 7, and 14 days after discontinuation of morphine treatment during the period when lights were on in the housing room and when the lights were off in the housing room (dark bars). Closed circles represent values obtained prior to discontinuing morphine treatment (and are the same for days 1 and 7) and open symbols represent values obtained after morphine treatment was discontinued. For clarity, each point summarizes data over 3 h for each monkey (±SEM). Two-factor repeated-measures ANOVA was followed by Dunnett's test to determine which points were significantly (*p<0.05) different from control (closed circles). For day 14, only data from two monkeys were included in both the control data and the data obtained after morphine treatment was discontinued and are analyzed separately from days 1 and 7. Ordinate: upper heart rate (beats per minute); middle body temperature (°C); bottom activity (counts per minute). Abscissa: time of day represented every 3 h