HINDERED DIFFUSION OF HIGH-MOLECULAR-WEIGHT COMPOUNDS IN BRAIN EXTRACELLULAR MICROENVIRONMENT MEASURED WITH INTEGRATIVE OPTICAL IMAGING

被引:221
作者
NICHOLSON, C
TAO, L
机构
[1] Department of Physiology and Biophysics, New York University Medical Center, New York
关键词
D O I
10.1016/S0006-3495(93)81324-9
中图分类号
Q6 [生物物理学];
学科分类号
071011 ;
摘要
This paper describes the theory of an integrative optical imaging system and its application to the analysis of the diffusion of 3-, 10-, 40-, and 70-kDa fluorescent dextran molecules in agarose gel and brain extracellular microenvironment. The method uses a precisely defined source of fluorescent molecules pressure ejected from a micropipette, and a detailed theory of the intensity contributions from out-of-focus molecules in a three-dimensional medium to a two-dimensional image. Dextrans tagged with either tetramethylrhodamine or Texas Red were ejected into 0.3% agarose gel or rat cortical slices maintained in a perfused chamber at 34-degrees-C and imaged using a compound epifluorescent microscope with a 10 x water-immersion objective. About 20 images were taken at 2-10-s intervals, recorded with a cooled CCD camera, then transferred to a 486 PC for quantitative analysis. The diffusion coefficient in agarose gel, D, and the apparent diffusion coefficient, D*, in brain tissue were determined by fitting an integral expression relating the measured two-dimensional image intensity to the theoretical three-dimensional dextran concentration. The measurements in dilute agarose gel provided a reference value of D and validated the method. Values of the tortuosity, lambda = (D/D*)1/2, for the 3- and 10-kDa dextrans were 1.70 and 1.63, respectively, which were consistent with previous values derived from tetramethylammonium measurements in cortex. Tortuosities for the 40- and 70-kDa dextrans had significantly larger values of 2.16 and 2.25, respectively. This suggests that the extracellular space may have local constrictions that hinder the diffusion of molecules above a critical size that lies in the range of many neurotrophic compounds.
引用
收藏
页码:2277 / 2290
页数:14
相关论文
共 58 条
[1]   RESTRICTED DIFFUSION OF MACROMOLECULES THROUGH AGAR-GEL MEMBRANES [J].
ACKERS, GK ;
STEERE, RL .
BIOCHIMICA ET BIOPHYSICA ACTA, 1962, 59 (01) :137-&
[2]  
AGARD DA, 1984, ANNU REV BIOPHYS BIO, V13, P191
[3]   FLUORESCENCE DIGITAL MICROSCOPY OF INTERSTITIAL MACROMOLECULAR DIFFUSION IN BURN INJURY [J].
AGGARWAL, SJ ;
SHAH, SJ ;
DILLER, KR ;
BAXTER, CR .
COMPUTERS IN BIOLOGY AND MEDICINE, 1989, 19 (04) :245-261
[4]   INTERSTITIAL PRESSURE, VOLUME, AND FLOW DURING INFUSION INTO BRAIN-TISSUE [J].
BASSER, PJ .
MICROVASCULAR RESEARCH, 1992, 44 (02) :143-165
[5]  
Born M., 1986, PRINCIPLES OPTICS, P705
[6]  
Caspers H., 1985, ION MEASUREMENTS PHY, P199
[7]  
CASTLEMAN KR, 1979, DIGITAL IMAGE PROCES, P351
[8]   DIRECT MEASUREMENT OF INTERSTITIAL CONVECTION AND DIFFUSION OF ALBUMIN IN NORMAL AND NEOPLASTIC TISSUES BY FLUORESCENCE PHOTOBLEACHING [J].
CHARY, SR ;
JAIN, RK .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 1989, 86 (14) :5385-5389
[9]   EXTRACELLULAR VOLUME DECREASES WHILE CELL-VOLUME IS MAINTAINED BY ION UPTAKE IN RAT-BRAIN DURING ACUTE HYPERNATREMIA [J].
CSERR, HF ;
DEPASQUALE, M ;
NICHOLSON, C ;
PATLAK, CS ;
PETTIGREW, KD ;
RICE, ME .
JOURNAL OF PHYSIOLOGY-LONDON, 1991, 442 :277-295
[10]   DRUG DIFFUSION WITHIN THE BRAIN [J].
FENSTERMACHER, J ;
KAYE, T .
ANNALS OF THE NEW YORK ACADEMY OF SCIENCES, 1988, 531 :29-39