Preparation and biodistribution of [125I]IBZM: a potential CNS D-2 dopamine receptor imaging agent.
A new CNS D-2 dopamine receptor imaging agent [125I]IBZM, (S)-3-[125I]-iodo-N-[(1-ethyl-2-pyrrolidinyl)] methyl-2-hydroxy-6-methoxybenzamide, was prepared by either an exchange reaction or by the chloramine-T method. After an i.v. injection, the agent easily passed through the blood-brain barrier and localized in the rat brain. At 2, 15, 30 and 60 min after the injection, the brain uptake was 2.9, 2.3, 1.8 and 0.7% dose/organ, respectively. Regional uptake ratio of striatum/cerebellum (target to nontarget ratio) increased from 1.4 at 30 s to 10.3 at 2 h after the i.v. injection. Digital autoradiography of rat brain sections showed high regional uptake in the caudate putamen and accumbens nucleus, areas known to have a high concentration of the D-2 dopamine receptor. The specific uptake at the D-2 dopamine receptor site was blocked by pretreatment with spiperone, a selective D-2 antagonist. When labeled with 123I (t1/2 = 13 h, 159 keV), [123I]IBZM may be useful for imaging the CNS D-2 dopamine receptor.
Kung
H F
HF
Department of Nuclear Medicine, SUNY, Buffalo.
Guo
Y Z
YZ
Billings
J
J
Xu
X
X
Mach
R H
RH
Blau
M
M
Ackerhalt
R E
RE
D000818:Animals; D001549:Benzamides / Q000493:pharmacokinetics*; D001921:Brain / Q000000981:diagnostic imaging*; D007457:Iodine Radioisotopes; D007553:Isotope Labeling / Q000379:methods; D008297:Male; D011759:Pyrrolidines / Q000493:pharmacokinetics*; D051381:Rats; D011954:Receptors, Dopamine / Q000000981:diagnostic imaging*; D017448:Receptors, Dopamine D2; D014018:Tissue Distribution; D014055:Tomography, Emission-Computed
D001549:Benzamides; D007457:Iodine Radioisotopes; D011759:Pyrrolidines; D011954:Receptors, Dopamine; D017448:Receptors, Dopamine D2; C055743:3-iodo-2-hydroxy-6-methoxy-N-((1-ethyl-2-pyrrolidinyl)methyl)benzamide