Blood-brain barrier permeability to sucrose and dextran after osmotic opening

1984 ◽  
Vol 247 (4) ◽  
pp. R634-R638 ◽  
Author(s):  
Y. Z. Ziylan ◽  
P. J. Robinson ◽  
S. I. Rapoport

Regional cerebrovascular permeability-surface area (PA) products were calculated for two nonelectrolyte tracers differing considerably in molecular weight and size [( 14C]sucrose: mol wt 340 daltons, radius 5 A; and [3H]dextran: mol wt approximately 79,000 daltons, radius approximately 65 A) in control (uninfused) rats and in rats 6, 35, and 55 min after the blood-brain barrier was opened by a 30-s infusion of 1.8 molal L(+)-arabinose into a carotid artery. In control brain regions, mean PA for [14C]sucrose was 10(-5) s-1, whereas PA was not measurable for [3H]dextran. Six minutes after arabinose infusion, PA for both substances increased dramatically to 10(-4) s-1 or more; PA then declined at 35 and 55 min after arabinose infusion, but more markedly for [3H]dextran than for [14C]sucrose. The results demonstrate a size-dependent, differential rate of closure of the blood-brain barrier after osmotic opening. This is shown to be consistent with a pore model with bulk flow for blood-brain barrier permeability after osmotic opening.

2006 ◽  
Vol 291 (6) ◽  
pp. H2660-H2668 ◽  
Author(s):  
Jason D. Huber ◽  
Reyna L. VanGilder ◽  
Kimberly A. Houser

This study investigated the effects of streptozotocin-induced diabetes on the functional integrity of the blood-brain barrier in the rat at 7, 28, 56, and 90 days, using vascular space markers ranging in size from 342 to 65,000 Da. We also examined the effect of insulin treatment of diabetes on the formation and progression of cerebral microvascular damage and determined whether observed functional changes occurred globally throughout the brain or within specific brain regions. Results demonstrate that streptozotocin-induced diabetes produced a progressive increase in blood-brain barrier permeability to small molecules from 28 to 90 days and these changes in blood-brain barrier permeability were region specific, with the midbrain most susceptible to diabetes-induced microvascular damage. In addition, results showed that insulin treatment of diabetes attenuated blood-brain barrier disruption, especially during the first few weeks; however, as diabetes progressed, it was evident that microvascular damage occurred even when hyperglycemia was controlled. Overall, results of this study suggest that diabetes-induced perturbations to cerebral microvessels may disrupt homeostasis and contribute to long-term cognitive and functional deficits of the central nervous system.


2018 ◽  
Vol 25 (9) ◽  
pp. 1073-1089 ◽  
Author(s):  
Santiago Vilar ◽  
Eduardo Sobarzo-Sanchez ◽  
Lourdes Santana ◽  
Eugenio Uriarte

Background: Blood-brain barrier transport is an important process to be considered in drug candidates. The blood-brain barrier protects the brain from toxicological agents and, therefore, also establishes a restrictive mechanism for the delivery of drugs into the brain. Although there are different and complex mechanisms implicated in drug transport, in this review we focused on the prediction of passive diffusion through the blood-brain barrier. Methods: We elaborated on ligand-based and structure-based models that have been described to predict the blood-brain barrier permeability. Results: Multiple 2D and 3D QSPR/QSAR models and integrative approaches have been published to establish quantitative and qualitative relationships with the blood-brain barrier permeability. We explained different types of descriptors that correlate with passive diffusion along with data analysis methods. Moreover, we discussed the applicability of other types of molecular structure-based simulations, such as molecular dynamics, and their implications in the prediction of passive diffusion. Challenges and limitations of experimental measurements of permeability and in silico predictive methods were also described. Conclusion: Improvements in the prediction of blood-brain barrier permeability from different types of in silico models are crucial to optimize the process of Central Nervous System drug discovery and development.


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