Article Figures & Data
Figures
- FIGURE 1.
Chemical structures of 2-18F-A-85380, 5-123I-I-A-85380, sazetidine, and 18F-ZW-104.
- FIGURE 2.
Baboon brain time–activity curves (SUV) after intravenous injection of 18F-ZW-104. Peak radioactivity in thalamus (▴) occurred at 50–60 min and was followed by clear washout. In regions with low nAChR densities, frontal cortex (•) and cerebellum (▪) washout was faster. Plasma (continuous line) and plasma-unchanged ZW-104 (dotted line) radioactivities are also displayed.
- FIGURE 3.
Logan plots in thalamus, frontal cortex, and cerebellum. For VT to be time-invariant in cerebellum, frontal cortex, and thalamus, 30, 45, and 55 min, respectively, are required.
- FIGURE 4.
Thalamic time–activity curves in control animal (▴) and after pretreatment with intravenous nicotine (•), 2,500 nmol/kg administered 30 min before the radiotracer, or unlabeled ZW-104 (♦), 500 nmol/kg administered 50 min before the radiotracer.
- FIGURE 5.
Whole-body distribution of 18F-ZW-104. Projection obtained 3 h after injection. Elimination of radioligand through biliary system and kidneys.
- FIGURE 6.
Sagittal sum images (from 45 to 90 min) after injection of 18F-ZW-104 and 2-18F-A-85380.
- FIGURE 7.
SUV curves of 18F-ZW-104 (filled symbols) and 2-18F-A-85380 (open symbols) in thalamus (▴) and in cerebellum (▪).
Tables
- TABLE 1
Inhibition Constants (Ki, nM) at nAChR Subtypes of Nicotinic Reference Ligands and of PET SPECT Radioligands
Ki (nmoles) Ligand α2β2 α2β4 α3β2 α3β4 α4β2 α4β4 Rat forebrain ZW-104 0.8 200 0.64 5,500 0.2 120 0.36 5-iodo-A-85380 0.031 41 0.47 280 0.059 24 0.11 2-fluoro-A-85380 1.44 181 3.02 3,680 1.33 188 0.47 Iodo-epibatidine 0.11 0.15 0.18 0.98 0.15 0.15 0.33 (−)-Nicotine 12 110 47 440 10 40 12 Inhibition constants of ligands at 6 defined rat nAChR subtypes and native nAChRs in rat forebrain (mainly α4β2 subtype) were measured. nAChRs were labeled with 3H-epibatidine. For comparison, data published previously are shown here, including Ki values of 5-iodo-A-85380, 2-fluoro-A-85380, iodo-epibatidine, and (−)-nicotine (4,6).
