Difference between revisions of "Support:Documents:Examples:Estimate Change of Neurotransmitter"
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dB/dt = K<sub>on</sub>[B<sub>max</sub> - B -B2 - B<sup>en</sup>]F - k<sub>off</sub>B | dB/dt = K<sub>on</sub>[B<sub>max</sub> - B -B2 - B<sup>en</sup>]F - k<sub>off</sub>B | ||
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| + | dF2/dt = K<sub>1</sub>C<sub>p</sub> - K<sub>2</sub>F2 - K<sub>on</sub>[B<sub>max</sub> - B -B2 - B<sup>en</sup>]F2 + k<sub>off</sub>B2 | ||
| + | |||
| + | dB2/dt = K<sub>on</sub>[B<sub>max</sub> - B -B2 - B<sup>en</sup>]F - k<sub>off</sub>B2 | ||
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Generally, there are two separate injections of tracer for ntPET: one for the rest condition (without any stimuli) and the other for the activation conditon (after a stimulus). | Generally, there are two separate injections of tracer for ntPET: one for the rest condition (without any stimuli) and the other for the activation conditon (after a stimulus). | ||
Revision as of 20:20, 25 February 2009
Model of Neurotransmitter PET (ntPET)
Overview
The changes of endogenous neurotransmitter by PET scanning after a stimulus has been proved with different approaches. In stead of detecting the increase or decrease of a neurotransmitter, it is important to characterize the temporal change of a neurotransmitter after a stimulus. Morris proposed the new technique (called ntPET) for capturing the dynamic changes of a neurotransmitter after a stimulus and demonstrated the ability of this method to reconstruct the temporal characteistics of an enhance in neurotransmitter concentration.
Here we present a general model of ntPET, which can be simplified to Morris' model.
This model can be described by the differential equations:
dF/dt = K1Cp - K2F - Kon[Bmax - B -B2 - Ben]F + koffB
dB/dt = Kon[Bmax - B -B2 - Ben]F - koffB
dF2/dt = K1Cp - K2F2 - Kon[Bmax - B -B2 - Ben]F2 + koffB2
dB2/dt = Kon[Bmax - B -B2 - Ben]F - koffB2
Generally, there are two separate injections of tracer for ntPET: one for the rest condition (without any stimuli) and the other for the activation conditon (after a stimulus).
Cp is the pasma concentration of tracer at the first injection (the "rest" condition).
F and B are free (unbound) and bound molar concentrations of tracer after the first injection
Cp2 is the pasma concentration of tracer at the second injection (the "activation" condition).
F2 and B2 are free (unbound) and bound molar concentrations of tracer after the second injection.
Fen and Ben are free and bound molar concentrations of a neurotransmitter released by endogenous ligand after a stimulus.