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| Int'l Paper Session - Effects of MDMA ("Ecstasy") on Discrimination Performance |
| Monday, May 30, 2005 |
| 3:00 PM–4:20 PM |
| Lake Ontario (8th floor) |
| Area: BPH |
| Chair: David N. Harper (Victoria University of Wellington, New Zealand) |
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| The Effects of Acute MDMA Administration on Discrimination Performance |
| Domain: Basic Research |
| DAVID N. HARPER (Victoria University of Wellington, New Zealand), Maree J. Hunt (Victoria University of Wellington, New Zealand), Charlotte Jane Kay (Victoria University of Wellington, New Zealand), Susan Schenk (Victoria University of Wellington, New Zealand) |
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| Abstract: Recent evidence in our laboratory indicates that the disruptive effects of acute MDMA ("ecstasy") on discrimination performance in discrete trial tasks might be the product of a disruption to the unchanging stimulus control elements of the task that remain constant across trials. This talk will cover the data from several different experiments (utilizing delayed matching-to-sample and radial-arm maze procedures). These studies indicate that although MDMA produces deficits in conditional discrimination performance (often characterized as deficits in 'working memory'), these deficits are dissimilar from those produced by a typical amnetic drug such as scopolamine and are better viewed as impairments with respect to what is often referred to as the 'reference' memory components of task performance. |
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| The Effect of Chronic MDMA Treatment on Pre-trained DMTS Performance and Acquisition of a DNMTS Rule in Rats |
| Domain: Basic Research |
| LINCOLN S. HELY (Victoria University of Wellington, New Zealand), David N. Harper (Victoria University of Wellington, New Zealand), Maree J. Hunt (Victoria University of Wellington, New Zealand), Susan Schenk (Victoria University of Wellington, New Zealand) |
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| Abstract: Evidence from rats, non-human primates and humans shows that the drug of abuse, 3,4-methylenedioxmetamphetamine (MDMA or “ecstasy”) has a profound neurotoxic effect on serotonin (5-HT) neurons in the brain. Human users often report impairment of memory and mnemonic function after long-term MDMA use yet there is relatively little evidence of such impairments in experimental animal studies. In this study rats that had previously learned the delayed matching-to-sample (DMTS) task were treated with a large dose of MDMA (n=17) (four injections of 10mg/kg over 6 hours) or vehicle (n=13) on a single day. Two-weeks later animals resumed DMTS test sessions. A small but significant overall deficit in accuracy was found for MDMA-treated animals for the five sessions post-treatment. At the conclusion of DMTS testing, rats were changed to the delayed non matching-to-sample task (DNMTS) and acquisition of this novel task was measured for the subsequent twenty test sessions. MDMA-treated animals showed no significant impairments in acquisition of the novel DNMTS at any delay tested. Therefore, chronic exposure to a high dose of MDMA impaired accuracy on the pretrained DMTS task, but did not have any effect on acquisition of the new DNMTS rule. |
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