Article Figures & Data
Figures
- FIGURE 1.
(A) Fraction of nonmetabolized 2-FA expressed as percentage of total plasma radioactivity (mean ± SEM; n = 6). (B) Typical time course of elimination of radioactivity from arterial blood plasma after 2-FA administration. Values represent mean ± SEM of total plasma radioactivity (•) and radioactivity from free parent compound in plasma (nonmetabolized 2-FA) (○) measured in 6 different monkeys and expressed as SUVs. To obtain SUVs, mean radioactivity (kBq/cm3) was normalized to injected dose (kBq) per gram of body weight, as follows: SUV = tissue radioactivity/dose radioactivity (13). (C) Dynamics of radioactivity accumulation in different structures after 2-FA administration. SUVs (mean ± SEM) in thalamus (○), midbrain (•), cortex (□), cerebellum (♦), and muscle (⋄) are presented.
- FIGURE 2.
Comparison of VDT values obtained with 1TCM, 2TCM, and Logan approaches in control (CTRL; n = 6) and in blocking (BLK; n = 4) studies. Results are expressed as mean ± SEM of VDT values obtained with different approaches. Note high consistency and similar variability among VDT values.
- FIGURE 3.
Effect of nicotine infusion during PET studies. (A) Representative dynamics of radioactivity accumulation in different structures after bolus administration of 2-FA. Nicotine infusion was initiated at 330 min. Regions displayed include thalamus (▴), cortex (♦), cerebellum (⋄), muscle (•), and blood (▵). (B) Average displacement induced by nicotine in 5 different experiments. Results are expressed as mean ± SEM of VDT values in cerebellum and muscle structures; data were collected during 1-h periods either before (⋄, ▵) or 2 h after (▴, ♦, •) infusion of nicotine.
- FIGURE 4.
Correlation of apparent BP* values measured with cerebellum (abscissa) or muscle (ordinate) as reference region. Results were obtained from 16 different monkeys. Significant correlations were noted in 3 brain areas (r = 0.91, 0.85, and 0.82 for thalamus, midbrain, and cortex, respectively).
- FIGURE 5.
Images showing that similar BP* values were obtained with cerebellum or muscle as reference region. (A) Representative MRI horizontal section at level of thalamus in squirrel monkey. (B) Fused MRI and PET images. (C and D) Images showing BP* values measured with muscle (C) and with cerebellum (D) as reference regions. (E) Difference between C and D, indicating similar values for whole brain with either muscle or cerebellum as reference region. (F) Same difference as in E but expressed as percentage of values obtained with cerebellum as reference region.
- FIGURE 6.
Effect of study duration on stability of BP* values measured with cerebellum (○) or muscle (•) as reference region. BP* values (mean ± SD; n = 5) are expressed as percentage deviation from value obtained with 7-h scanning time. (A) Thalamus. (B) Cortex.
- FIGURE 7.
Effect of mass of administered radioligand on apparent BP* values measured in thalamus with cerebellum as reference region. ED50 of this effect (3.2 ± 0.3 nmol/kg) was calculated on basis of results obtained for 4 animals in 9 separate PET studies with bolus administration of 2-FA at doses ranging from 0.1 to 6.1 nmol/kg. Obtained values were expressed as percentage of control values obtained when radioligand was injected at lowest dose (0.1–0.12 nmol/kg). Control BP* values in 4 animals used in this experiment were 3.0, 2.7, 2.5, and 2.4.
Tables
- TABLE 1
Comparison of BP* Values in Thalamus and Temporal Cortex, Calculated from VDT and VDnd Values Obtained During Blocking Studies (BP*blk) or Calculated with SRTM Approach and Muscle (BP*msl) or Cerebellum (BP*cb) as Reference Region
Thalamus Cortex Monkey BP*blk BP*msl % Change* BP*cb % Change* BP*blk BP*msl % Change* BP*cb % Change* 1 3.10 3.13 1.0 2.81 −9.3 0.97 1.07 9.9 0.84 −13.4 2 2.50 2.23 −10.6 2.34 −6.6 0.70 0.83 18.5 0.66 −6.4 3 1.60 1.56 −2.4 1.45 −9.4 0.40 0.40 1.0 0.40 0.0 4 2.40 2.71 12.9 2.18 −9.2 0.88 1.03 17.4 0.75 −14.8 Mean 2.40 2.41 0.2 2.19 −8.6 0.74 0.83 11.7 0.66 −8.6 SD 0.62 0.67 9.8 0.56 1.3 0.25 0.30 8.1 0.19 6.8 ↵* Percentage change from BP*blk value in respective brain region.
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