The individual and combined effects of phenmetrazine (shaded/gray area)
and LY379268 (0.03 mg/kg, green; 0.30 mg/kg, blue) on breakpoints during
progressive-ratio responding for cocaine expressed as raw breakpoints (left
column; A, C, E) and as a percent of baseline (right column; B, D, F). In panels
A, C, and E, bars are plotted for linear breakpoints on left y-axis and
corresponding final response ratios on log scale are plotted on right y-axis for
comparison. Number of animals: A, B (n=6); C, D (n=8); E, F (n=6). Red line
signifies baseline for phenmetrazine alone and combined treatment.
*p<0.05, **p<0.01,
***p<0.001, comparison to respective baseline
breakpoints. Δp<0.05,
ΔΔp<0.01, combined
treatment compared to the respective LY379268 dose. Data points are expressed as
mean±SEM.