PPT Slide
Notes:
Contingent saline engendered approximately 16% of cocaine control responding. Since there was no pre-session stimulus change or priming injection to predict which solution was available to the animal for self-injection, a small amount of “sampling” occurred at the beginning of each saline session but generally abated within 10 infusions.
Self-administration of MDMA and its stereoisomers peaked at approximately 70% of cocaine control. To assess the role of duration of drug action in self-administration under this schedule, we substituted a few doses of methamphetamine (longer duration -- more like MDMA than like cocaine.)
The truncated dose response curve for methamphetamine shows that a drug with an extended duration of action can maintain an equal number of injections as cocaine under this schedule.
There was no marked difference in potency or the maximum percent of cocaine control responding maintained by racemic MDMA or the stereoisomers. Responding for (+/-)-MDMA, S(+)-MDMA, and R(-)-MDMA all peaked at approximately 70% of cocaine control responding.