Steady-state theory for quantitative microdialysis of solutes and water in vivo and in vitro

Journal Article · Mon Jan 01 00:00:00 EST 1990 · Life Sciences; (USA)

DOI:https://doi.org/10.1016/0024-3205(90)90043-Q· OSTI ID:6530195

Bungay, P M; Morrison, P F; Dedrick, R L ^[1]

---

1. National Institutes of Health, Bethesda, MD (USA)

A mathematical framework was developed to provide a quantitative basis for either in vivo tissue or in vitro microdialysis. Established physiological and mass transport principles were employed to obtain explicit expressions relating dialysate concentration to tissue extracellular concentration for in vivo applications or external medium concentration in vitro probe characterization. Some of the important generalizations derived from the modeling framework are: (i) the microdialysis probe can perturb the spatial concentration profile of the substance of interest for a considerable distance from the probe, (ii) for low molecular weight species the tissue is generally more important than the probe membrane in determining the dialysate-to-tissue concentration relationship, (iii) metabolism, intracellular-extracellular and extracellular-microvascular exchange, together with diffusion, determine the role of the tissue in vivo probe behavior, and, consequently, (iv) in vitro calibration procedures could be useful for characterizing the probe, if properly controlled, but have limited applicability to in vivo performance. The validity of the proposed quantitative approach is illustrated by the good agreement obtained between the predictions of a model developed for tritiated water (({sup 3})H{sub 2}O) in the brain and experimental data taken from the literature for measurements in the caudoputamen of rats. The importance of metabolism and efflux to the microvasculature is illustrated by the wide variation in predicted tissue concentration profiles among ({sup 3})H{sub 2}O, sucrose and dihydroxyphenylacetic acid (DOPAC).

• OSTI ID: 6530195
• Journal Information: Life Sciences; (USA), Vol. 46:2; ISSN 0024-3205
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ANIMAL TISSUES
METABOLISM
SOLUTES
DIALYSIS
WATER
BRAIN
CELL MEMBRANES
IN VITRO
IN VIVO
MATHEMATICAL MODELS
MEMBRANE TRANSPORT
STEADY-STATE CONDITIONS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
BODY
CELL CONSTITUENTS
CENTRAL NERVOUS SYSTEM
HYDROGEN COMPOUNDS
ISOTOPE APPLICATIONS
MEMBRANES
NERVOUS SYSTEM
ORGANS
OXYGEN COMPOUNDS
SEPARATION PROCESSES
TISSUES
550501* - Metabolism- Tracer Techniques