From: [d--n] at [cam.ov.com] (Donald T. Davis) Newsgroups: alt.drugs,alt.psychoactives,sci.med.psychobiology Subject: Re: MDMA Neurophamacology Date: 23 Jun 1994 22:46:04 -0400 this message comprises an exchange of several messages between me and matt plunkett, which followed his responding to my comments about mdma's neurotoxicity. it starts out with a lot of technical matter, which matt clarified as the conversation progressed. i figured you all might be interested, so i'm posting it. -don davis ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Don wrote: > it sounds like the psychological action may depend on the > neurotoxicity, though they could just share a common cause. matt responded: TITLE: Nonneurotoxic tetralin and indan analogues of 3,4-(methylenedioxy)amphetamine (MDA). [Nonneurotoxic tetralin and indan analogues of 3 4 methylenedioxyamphetamine mda] AUTHOR: Nichols, D E (Dep. Med. Chem., Sch. Pharmacy Pharmacal Sci., Purdue Univ., West Lafayette, Indiana 47907.); Brewster, W K; Johnson, M P; Oberlender, R; Riggs, R M PUBLICATION: Journal Of Medicinal Chemistry. 1990 33(2):702-710. J Med Chem. ABSTRACT: Four cyclic analogues of the psychoactive phenethylamine derivative 3,4-(methylenedioxy)amphetamine were studied. These congeners, 5,6- and 4,5-(methylenedioxy)-2-aminoindan (3a and 4a, respectively), and 6,7- and 5,6-(methylenedioxy)-2-aminotetralin (3b and 4b, respectively) were tested for stimulus generalization in the two-lever drug-discrimination paradigm. Two groups of rats were trained to discriminate either LSD tartrate (0.08 mg/kg) from saline, or (.+-.)-MDMA.cntdot.HCl (1.75 mg/kg) from saline. In addition, a 2-aminoindan (5a) and 2-aminotetralin (5b) congener of the hallucinogenic amphetamine 1-(2,5-dimethoxy-4-methylphenyl)-2-aminopropane (DOM) were also evaluated. None of the methylenedioxy compounds substituted in LSD-trained rats, while both 3a and 3b fully substituted in MDMA-trained rats. Compounds 4a and 4b did not substitute in MDMA-trained rats. Compounds 5a and 5b did not substitute in MDMA-trained rats, although 5a substituted in LSD-trained rats, but with relatively low potency compared to its open-chain counterpart. In view of the now well-established serotonin neurotoxicity of 3,4-(methylenedioxy)amphetamine and its N-methyl homologue 1, 3a and 3b were evaluated and compared to 1 for similar toxic effects following a single acute dose of 40 mg/kg sc. Sacrifice at 1 week showed that neither 3a nor 3b depressed rat cortical or hippocampal 5-HT or 5-HIAA levels nor were the number of binding sites (Bmax) depressed for [3H]paroxetine. By contrast, and in agreement with other reports, 1 significantly depressed all three indices of neurotoxicity. These results indicate that 3a and 3b have acute behavioral pharmacology similar to 1 but that they lack similar serotonin neurotoxicity. Oxidation at the 6-position on the aromatic ring creates the toxic metabolite; blocking this position creates a non-neurotoxic, equally effective analogue . . . matt (Matthew James Plunkett <[p--nk--t] at [uclink.berkeley.edu]>) On Thu, 23 Jun 1994, Donald T. Davis wrote: > thanks for your response, but while i think i got the punchline, > i certainly didn't understand the prologue (though i'd like to). > the main obstacle for me was the notion of lsd substituting for > the other drugs (which i guessed are relatives of mdma). what's > this notion of substitution, please? > -don > matt responded, The idea is that you get a rat to tell the difference between lsd and saline, and between mdma and saline. If you take an mdma trained rat and give it lsd, it doesn't know the difference between lsd and saline. So it's a crude way to tell the differences between drug classes. So these molecules they made, some of them, showed cross substitution with mdma. The logical next experiment would be to give them to a human and have her record what happens. . . Take care, matt don replied: ok, now i understand the abstract (thanks for the explanation). and, now that i understand, i stick to my guns after all: it may be that mdma's permanent effects depend on the neurotoxicity, even though the temporary effects do not. -don davis boston, ma