The Dopamine Stabilizer (−)-OSU6162 Occupies a Subpopulation of Striatal Dopamine D2/D3 Receptors: An [11C]Raclopride PET Study in Healthy Human Subjects.

Autor: Tolboom, Nelleke, Berendse, Henk W, Leysen, Josee E, Yaqub, Maqsood, van Berckel, Bart NM, Schuit, Robert C, Ponsen, Mirthe M, Bakker, Esther, Hoetjes, Nikie J, Windhorst, Albert D, Carlsson, Maria L, Lammertsma, Adriaan A, Carlsson, Arvid
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Zdroj: Neuropsychopharmacology; Jan2015, Vol. 40 Issue 2, p472-479, 8p, 1 Color Photograph, 2 Charts, 2 Graphs
Abstrakt: (−)-OSU6162 is a dopamine stabilizer that can counteract both hyperdopaminergic and hypodopaminergic states. In this study, D2/D3 receptor occupancy of (−)-OSU6162 in the human brain was investigated using positron emission tomography (PET). Twelve male healthy volunteers underwent [11C]raclopride PET scanning before and 1 h after a single oral dose of (−)-OSU6162 (15-90 mg). Blood samples for determination of (−)-OSU6162 and prolactin plasma levels were collected at Tmax. Parametric images of [11C]raclopride binding potential relative to nondisplaceable tissue (cerebellar grey matter) uptake (BPND) at baseline and after (−)-OSU6162 administration were generated using the simplified reference tissue model. MRI-based regions of interest were defined for the striatum, composed of caudate nucleus and putamen, and projected onto the co-registered parametric [11C]raclopride BPND image. Furthermore, three striatal subregions, ie, anterior dorsal caudate, anterior dorsal putamen, and ventral striatum, were defined manually and additionally analyzed. Plasma concentrations of (−)-OSU6162, ranging from 0.01 to 0.9 μM, showed a linear relationship with prolactin levels, reflecting blockade of pituitary D2 receptors. A concentration-dependent increase in striatal D2/D3 receptor occupancy was observed, reaching a value of about 20% at an (−)-OSU6162 plasma level of 0.2 μM, and which for higher concentrations leveled off to a maximal occupancy of about 40%. Findings were similar in the striatal subregions. The present data corroborate the notion that (−)-OSU6162 binds preferentially to a subpopulation of D2/D3 receptors, possibly predominantly extrasynaptic, and this may form the basis for the dopamine-stabilizing properties of (−)-OSU6162. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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