Related Experiment Video

Updated: Aug 2, 2026

Rat Model of Blood-brain Barrier Disruption to Allow Targeted Neurovascular Therapeutics
08:43

Rat Model of Blood-brain Barrier Disruption to Allow Targeted Neurovascular Therapeutics

Published on: November 30, 2012

Active transport of 131-I across the blood-brain barrier

H Davson, J R Hollingsworth

    The Journal of Physiology
    |September 1, 1973
    PubMed

    The ventricular space of rabbits was perfused with a low-viscosity silicone oil for the purpose of (1) collecting freshly secreted cerebrospinal fluid (c.s.f.) uninfluenced by diffusional exchanges with the brain and (2) studying passage of solutes from the blood into the brain, uncomplicated by exchanges with c.s.f. The freshly secreted c.s.f. appeared as fine droplets suspended in the less dense silicone, and accumulated at the bottom of the collected silicone. Studies on the penetration of (24)Na from blood into this fluid indicated that considerable exchanges with the brain had occurred between its secretion and collection, in spite of this method of collection. The second objective was attained, in that the exchanges between the freshly secreted fluid and the brain were quantitatively insufficient to affect the measure of kinetics of uptake by brain from the blood. In consequence, it was possible to demonstrate unequivocally that the increased uptake by brain of (131)I, when treated with perchlorate, was due to inhibition of an active process occurring across the blood-brain barrier. Other studies, involving ventriculo-cisternal perfusion with artificial c.s.f., lent further support to this concept. (131)I distribution is some 32% of the brain weight, a figure close to the ;chloride-space'.

    More Related Videos

    High-resolution Confocal Imaging of the Blood-brain Barrier: Imaging, 3D Reconstruction, and Quantification of Transcytosis10:30

    High-resolution Confocal Imaging of the Blood-brain Barrier: Imaging, 3D Reconstruction, and Quantification of Transcytosis

    Published on: November 16, 2017

    An In Vivo Blood-brain Barrier Permeability Assay in Mice Using Fluorescently Labeled Tracers09:35

    An In Vivo Blood-brain Barrier Permeability Assay in Mice Using Fluorescently Labeled Tracers

    Published on: February 26, 2018

    Related Concept Videos

    The Blood-brain Barrier00:49

    The Blood-brain Barrier

    Overview
    Physiological Barriers01:25

    Physiological Barriers

    Physiological barriers are semi-permeable cellular structures restricting drug diffusion into intracellular compartments and tissues. There are six types of physiological barriers: blood endothelial, cell membrane, blood-brain, blood-cerebrospinal fluid (CSF), blood-placenta, and blood-testis barriers.
    The blood endothelial barrier is the most porous of these. It allows all small ionized, un-ionized, and lipophilic molecules to pass through the endothelial lining into the interstitial space...
    Cellular Membranes and Drug Transport01:24

    Cellular Membranes and Drug Transport

    Drugs must traverse multiple biological barriers, such as multi-layered skin, single-layered intestinal epithelium, and the plasma membrane, to reach their target sites within the body. The plasma membrane, a highly structured composite of phospholipids, carbohydrates, and proteins, is the cell's protective boundary, facilitating selective substance exchange.
    Phospholipids arrange themselves into a bilayer, with hydrophilic heads oriented outward and hydrophobic tails facing inward.
    Pore Transport and Ion-Pair Transport01:17

    Pore Transport and Ion-Pair Transport

    Pore transport and ion-pair formation are critical mechanisms for the absorption and distribution of drugs in the body.
    Pore transport, also known as convective transport, is a process where small molecules like urea, water, and sugars rapidly cross cell membranes as though there were channels or pores in the membrane. Although direct microscopic evidence is limited  but the concept of pores or channels is widely accepted based on physiological evidence. Despite the lack of direct microscopic...
    Carrier-Mediated Transport01:06

    Carrier-Mediated Transport

    Carrier-mediated transport is a pivotal process in drug absorption, particularly for lipid-insoluble drugs, and encompasses facilitated diffusion and active transport. Facilitated diffusion allows drugs to move along their concentration gradient without energy expenditure, while active transport utilizes ATP to drive drug movement against this gradient.
    Active transport involves two types of membrane-spanning transporters: uptake and efflux. Uptake transporters are expressed in the small...
    Active Transport01:14

    Active Transport

    Active transport is a critical biological process that allows cells to move solutes against an electrochemical gradient. This process requires direct energy input and is characterized by its selectivity, saturability, and susceptibility to competitive inhibition.
    Primary active transporters, like Na+, K+ and -ATPase, directly utilize ATP to move ions across the membrane. These transporters play significant roles in various physiological processes. For instance, Na+, K+ and -ATPase maintain...