Time course of phenmetrazine effects on responding maintained by food and
cocaine (0.01–0.1 mg/kg/injection). Data obtained during availability of
0.01, 0.032, and 0.1 mg/kg/injection cocaine are shown in the top, middle, and
bottom rows of graphs, respectively. Data obtained during saline treatment are
shown in the left column, and data obtained during phenmetrazine treatment are
shown on the right. Abscissae, consecutive days of treatment. All treatments
were implemented for a period of 7 days. The shaded region in the middle right
shows cocaine- and food-maintained responding during the 7 days after
termination of phenmetrazine treatment (post-treatment days 1–7,
P1–P7). Left ordinates, number of injections per day (maximum = 80).
Right ordinates, number of food pellets per day (maximum = 100). All points
show mean ± S.E.M. in three monkeys.