| Autor: |
L H, Pinborg, C, Videbaek, G M, Knudsen, C G, Swahn, C, Halldin, L, Friberg, O B, Paulson, N A, Lassen |
| Rok vydání: |
2000 |
| Předmět: |
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| Zdroj: |
Synapse (New York, N.Y.). 36(4) |
| ISSN: |
0887-4476 |
| Popis: |
The iodinated benzamide epidepride, which shows a picomolar affinity binding to dopamine D(2) receptors, has been designed for in vivo studies using SPECT. The aim of the present study was to apply a steady-state condition by the bolus/infusion approach with [(123)I]epidepride for the quantification of striatal and extrastriatal dopamine D(2) receptors in humans. In this way the distribution volume of the tracer can be determined from a single SPECT image and one blood sample. Based on bolus experiments, an algorithm using conventional convolution arguments for prediction of the outcome of a bolus/infusion (B/I) experiment was applied. It was predicted that a B/I protocol with infusion of one-third of the initial bolus per hour would be appropriate. Steady-state conditions were attained in extrastriatal regions within 3-4 h but the infusion continued up to 7 h in order to minimize the significance of individual differences in plasma clearance and binding parameters. A steady-state condition, however, could not be attained in striatal brain regions using a B/I protocol of 20 h, even after 11 h. Under near steady-state conditions a striatal:cerebellar ratio of 23 was demonstrated. Epidepride has a unique signal-to-noise ratio compared to [(123)I]IBZM but present difficulties for steady-state measurements of striatal regions. The bolus/infusion approach is particularly feasible for quantification of the binding potential in extrastriatal regions. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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