Assessment of the Reinforcing Properties of Orally Administered MDMA ('Ecstasy') in Rats
Study at a glance
AI-extracted from the abstract| Characteristics | Experimental study |
|---|---|
| Population | Rats |
| Intervention | MDMA |
| Topics | MDMA |
| Key findings | Orally delivered MDMA maintained self-administration in rats, but demand-curve analysis showed that responding for MDMA was more elastic (lower Pmax) than for saccharin alone, indicating that saccharin was a stronger reinforcer. MDMA's reinforcing efficacy via oral route appears low. |
Abstract
The so-called “party drug” 3,4-Methylenedioxymethamphetamine (MDMA, or ecstasy) may share many of the addictive properties common to other CNS stimulants. In humans MDMA is primarily consumed orally in one more pills per session. However, animal research has mostly focused on examining the effects of MDMA as a function of other routes of administration. Route of administration can have profound effects on the subjective and reinforcing properties of drugs of abuse. This thesis assessed the locomotor-activating and reinforcing properties of MDMA when delivered orally. MDMA-induced hyperlocomotion was used to examine magnitude of response and onset of action as a function of ip, sc and oral administration. Significant route-dependant effects were found with ip producing higher locomotor activity than sc and oral respectively. Onset of action was slower for subcutaneous administration compared with both ip and oral administration. The reinforcing properties of MDMA were examined by use of the self-administration procedure. Oral MDMA self-administration was firstly examined using simple schedules of reinforcement as a function of two different vehicle substrates, water (under water deprivation) and saccharin. Oral MDMA maintained responding and reliable dose-response curves were obtained under both water and saccharin vehicle conditions. However, both saccharin and water vehicle conditions also acted as strong reinforcers in these studies. Further studies utilising a behavioural economic approach were conducted in order to delineate the reinforcing effects of MDMA from that of its parent vehicle. In addition, demand-curve analysis using both the Linear-Elasticity model (Hursh et al., 1988, 1989) and the Exponential Model of Demand (Hursh & Silberberg, 2008) were compared in order to evaluate each model and assess the relative reinforcing efficacy of oral MDMA. Demand curves for the oral self-administration of MDMA revealed that responding for MDMA was more elastic (lower Pmax) than responding for saccharin-alone indicating that saccharin functioned as stronger reinforcer than did MDMA+saccharin. The results of these studies provide evidence for the positive-reinforcing effects of MDMA when it is delivered via the oral route of administration, however, the relative reinforcing efficacy of orally delivered MDMA appears to be low.
Comparable studies
Other preclinical and animal studies on MDMA, most cited first.
Citations in the library
Cites 50
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- Gender differences in the subjective effects of MDMA Psychopharmacology March 5, 2001
- Human psychopharmacology of Ecstasy (MDMA): a review of 15 years of empirical research Human Psychopharmacology: Clinical and Experimental December 1, 2001
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