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Quantitative dual‐probe microdialysis: mathematical model
and analysis
Author(s) -
Chen Kevin C.,
Höistad Malin,
Kehr Jan,
Fuxe Kjell,
Nicholson Charles
Publication year - 2002
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.2002.00792.x
Subject(s) - microdialysis , diffusion , thermal diffusivity , biological system , interstitial space , interstitial fluid , chemistry , biomedical engineering , mannitol , extracellular , materials science , thermodynamics , pathology , physics , biology , biochemistry , medicine
Steady‐state microdialysis is a widely used technique to monitor the concentration changes and distributions of substances in tissues. To obtain more information about brain tissue properties from microdialysis, a dual‐probe approach was applied to infuse and sample the radiotracer, [ 3 H]mannitol, simultaneously both in agar gel and in the rat striatum. Because the molecules released by one probe and collected by the other must diffuse through the interstitial space, the concentration profile exhibits dynamic behavior that permits the assessment of the diffusion characteristics in the brain extracellular space and the clearance characteristics. In this paper a mathematical model for dual‐probe microdialysis was developed to study brain interstitial diffusion and clearance processes. Theoretical expressions for the spatial distribution of the infused tracer in the brain extracellular space and the temporal concentration at the probe outlet were derived. A fitting program was developed using the simplex algorithm, which finds local minima of the standard deviations between experiments and theory by adjusting the relevant parameters. The theoretical curves accurately fitted the experimental data and generated realistic diffusion parameters, implying that the mathematical model is capable of predicting the interstitial diffusion behavior of [ 3 H]mannitol and that it will be a valuable quantitative tool in dual‐probe microdialysis.