Single photon emission tomography measurement of benzodiazepine receptor number and affinity in primate brain: a constant infusion paradigm with [123I]iomazenil.
Benzodiazepine receptor number and affinity were measured in vivo with single photon emission tomography (SPECT). Following an initial bolus injection, the radiotracer [123I]iomazenil was infused at a constant rate for 5 to 8 h. This procedure induced a state of sustained equilibrium at the receptor level. Nondisplaceable activity was measured after injection of a receptor saturating dose of flumazenil. Experiments performed at high and low specific activity permitted estimation of an equilibrium binding affinity constant of 0.47 nM and a maximum binding capacity of 127 nM in occipital cortex.
Laruelle
M
M
Department of Psychiatry, Yale University School of Medicine, New Haven, CT.
Abi-Dargham
A
A
Rattner
Z
Z
al-Tikriti
M S
MS
Zea-Ponce
Y
Y
Zoghbi
S S
SS
Charney
D S
DS
Price
J
J
Frost
J J
JJ
Hoffer
P B
PB
D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects*; D005442:Flumazenil / Q000031:analogs & derivatives*; D066298:In Vitro Techniques; D007457:Iodine Radioisotopes; D010215:Papio; D011963:Receptors, GABA-A / Q000187:drug effects*; D015899:Tomography, Emission-Computed, Single-Photon
D007457:Iodine Radioisotopes; D011963:Receptors, GABA-A; D005442:Flumazenil; C063038:iomazenil