The other night , but it "poofed" on me
Great story line post Ron.
First of all, chemically, ecstacy has the two hydroxyl groups on the aromatic ring of the "almost dopamine" structure, tied together by a "methylene" group(one carbon atom, balanced off with two hydrogen atoms).
This is probably responsible for it's good CNS penetrability, as the naked hydroxyl groups are not exactly neutral atomic substituents, but instead are slightlly acidic. The neutral "methylendioxy" group itself is in a "tied back" configuration, but amply mimics the two "naked" hydroxyl groups of the dopamine structure.
And yes, NMDA acts on 5HT-2 receptors, which are responsible for it's "psychotomimetic" properties, that is massive release of serotonin, and while said not to act at dopamine receptors, it has such a similar structure to dopamine itself that it is no wonder why we see dopaminergic effects (at either pre or post synaptic D recptors). The answer to this question is easily seen in structural comparison.
And you can't keep pumping up the serotonin system indefinitely, sooner or later that pump becomes "damaged" if it is continually stimulated. Then you have damaged a very important neurotransmitter system involved in mood regulation. People coming off a long binge of NMDA have been known to commit suicide. cs