Assessment of endogenous dopamine release by methylphenidate challenge using iodine-123 iodobenzamide single-photon emission tomography.
This double-blind, placebo-controlled study assessed pharmacologically induced endogenous dopamine (DA) release in healthy male volunteers (n=12). Changes in endogenous DA release after injection of the psychostimulant drug methylphenidate were evaluated by single-photon emission tomography (SPET) and constant infusion of iodine-123 iodobenzamide ([123I]IBZM), a D2 receptor radioligand that is sensitive to endogenous DA release. Methylphenidate induced displacement of striatal [123I]IBZM binding, resulting in a significantly decrease in the specific to non-specific [123I]IBZM uptake ratio (average: 8.6%) in comparison with placebo (average: -1.9%). Moreover, injection of methylphenidate induced significant behavioural responses on the following items: excitement, anxiety, tension, and mannerisms and posturing. The results of this study demonstrate the feasibility of using constant infusion of [123I]IBZM and SPET imaging to measure endogenous DA release after methylphenidate challenge and to investigate neurochemical aspects of behaviour.
Booij
J
J
Graduate School of Neurosciences, Department of Nuclear Medicine, Academic Medical Center, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
Korn
P
P
Linszen
D H
DH
van Royen
E A
EA
D000328:Adult; D001519:Behavior / Q000187:drug effects; D001549:Benzamides; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism; D000697:Central Nervous System Stimulants; D004298:Dopamine / Q000378:metabolism*; D018492:Dopamine Antagonists; D018765:Dopamine Uptake Inhibitors; D004311:Double-Blind Method; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D008774:Methylphenidate; D011759:Pyrrolidines; D015899:Tomography, Emission-Computed, Single-Photon
D001549:Benzamides; D000697:Central Nervous System Stimulants; D018492:Dopamine Antagonists; D018765:Dopamine Uptake Inhibitors; D007457:Iodine Radioisotopes; D011759:Pyrrolidines; D008774:Methylphenidate; C055743:3-iodo-2-hydroxy-6-methoxy-N-((1-ethyl-2-pyrrolidinyl)methyl)benzamide; D004298:Dopamine