Synapse
July 14, 2004
Pedro Rosa‐neto, Albert Gjedde, Aage Kristian Olsen Alstrup et al.
39 citations
MDMA (Ecstasy) reduces the binding of two different radioligands to dopamine D2-like receptors in the striatum of living pigs, as measured by PET. The binding potential of [11C]raclopride fell by 35% at 45 minutes and 22% at 165 minutes after MDMA infusion, similar to changes caused by d-amphetamine. Unexpectedly, the binding of [11C]NMSP also decreased, by 30% in the first scan and 50% in the second, unlike its typical insensitivity to dopamine release. The simultaneous release of dopamine and serotonin by MDMA may explain the progressive decline in NMSP binding.
Synapse
April 5, 2007
Paul Cumming, Mette Møller, Kjeld Benda et al.
28 citations
The psychostimulant MDMA (ecstasy) causes degeneration of serotonin nerve endings in the forebrain of rodents, nonhuman primates, and human users. To study this in a large animal without using primates, researchers used PET scans to map serotonin transporters and 5HT1A receptors in the brains of Göttingen minipigs before and after MDMA treatment. Total doses above 20 mg/kg reduced serotonin transporter binding: a mean 42 mg/kg dose caused a 32% decrease in the midbrain and thalamus and a 53% decrease in forebrain structures. This loss did not consistently alter 5HT1A receptor binding. The number of serotonin-producing neurons in the dorsal raphé nucleus (about 95,000 in normal animals) remained unchanged.
Synapse
January 1, 2005
Luciano Minuzzi, George G. Nomikos, Mark Wade et al.
25 citations
LSD reduces the binding potential of a dopamine D2/3 receptor tracer in the striatum of pigs, suggesting a direct interaction with these receptors. In a PET study, the binding potential of [11C]raclopride decreased by 19% four hours after LSD administration, without changes in cerebral blood flow. In vitro experiments showed LSD displaces the tracer from pig brain tissue with an IC50 of 275 nM, and a two-site model indicated a subnanomolar component comprising 20% of binding. Microdialysis in rats found no changes in dopamine or its metabolites. These findings indicate LSD directly occupies a portion of dopamine D2/3 receptors, which may contribute to its psychoactive effects.