Kinetics of sodium transfer from blood to brain of the dog

Gf, Brooks; Koch, Alan; Wong, Joseph T.Y.

doi:10.1152/ajplegacy.1970.218.3.693

Cited by 7 publications

(3 citation statements)

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“…Graphic or mathematical integration, using their forcing function and a single rate constant for turnover in the system, shows that a better fit for their results is obtained with a rate constant of 0004 min1, which is 346 BLOOD-BRAIN BARRIER close to the value of 0*0052 min-found by Davson & Luck (1957). For the brain, Olsen & Rudolph found the increase in activity to parallel that in fluid, which is at odds with the recent study of Brooks, Koch & Wong (1970) in which the rate constant for brain was computed as 0-0017 min-'. These investigators had to contend with a system of measurement and control so complicated that it might have impaired the analysis.…”

Section: Discussionmentioning

confidence: 82%

The permeation of several materials into the fluids of the rabbit's brain

Davson¹,

Welch²

1971

The Journal of Physiology

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SUMMARY1. 24Na, 36CI and 35S thiourea were infused i.v. in rabbits according to schedules designed to yield approximately level activity in plasma for periods up to 5 hr. Cerebrospinal fluid was sampled before ending the experiment by decapitation and the radioactivities in cerebrospinal fluid and in homogenized brain were compared in each case to a time weighted mean value for plasma.2. The results are considered in terms of a simplified model which specifically acknowledges the continuity of the extracellular and cerebrospinal fluids and thus the coupling between processes which occur at the interfaces bordering those fluids.3. From the rate constants for exchange across the blood-brain interface that were necessary for simulation of the observed behaviours, permeability coefficients for that interface were estimated for the materials studied and, from experiments of others, for 42K.

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Section: Discussionmentioning

confidence: 82%

The permeation of several materials into the fluids of the rabbit's brain

Davson¹,

Welch²

1971

The Journal of Physiology

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“…Of these extracellular-type molecules, only mannitol in all three areas (Figs. [2][3][4] and sucrose in the spinal cord (Table 3) appear to have distributed in a space of a size approaching that of the ECS by 20 h, illustrating the relative tightness of the blood-brain barrier in these fish to such compounds. The l-and 4-h mannitol and sucrose ratios of the telencephalon and medulla, when corrected for their respective tissue plasma volumes, are slightly higher but comparable to the whole-brain values of the rat reported by Sisson and Oldendorf (25) for the same two times.…”

Section: Discussionmentioning

confidence: 98%

CNS, CSF, and extradural fluid uptake of various hydrophilic materials in the dogfish

Fenstermacher¹,

Patlak²

1977

American Journal of Physiology-Regulatory, Integrative and Comp

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The distribution of 10 radioactively labeled materials from blood to CSF, extradural fluid (EDF), telencephalon (cerebrum), medulla, and spinal cord was studied in the dogfish shark. Plasma volumes, blood flows, and blood-to-tissue or fluid-transfer half-times (t1/2) were calculated from these distribution data. Blood-EDF exchange occurred at slow but similar rates for all tracers. Urea uptake by the CSF was very rapid compared to that of the other compounds and may be facilitated by a special mechanism. The tissue plasma spaces of all three CNS regions were small (1.1-1.5%). The calculated rates of tissue blood flow (in ml/g-min) were 0.11 for telencephalon and medulla and 0.055 for spinal cord. Choroid plexus blood flow was estimated to be 2.3 ml/g-min, a surprisingly high rate. Transport between blood and tissue was most rapid for water ethylene glycol and slowest for inulin. The tissue t1/2's of urea indicated that a significant portion of this compound's net uptake by periventricaul brain tissue occurred via the CSF.

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“…Stulc studied sodium exchange in mice and was particularly interested in the very fast first compartment; he found three compartments with tj of 20 sec, 1 hr, and 7 hr, respectively (Stulc, 1967a, b). In the dog, external collimation has been used to ascertain the rates of blood-cranial exchange (Brooks, Koch & Wong, 1970).…”

Section: Na Kinetics In Rat Tissues the Brain Intracellular 24na Spmentioning

confidence: 99%

A compartmental analysis of ²⁴Na kinetics in rat cerebrum, sciatic nerve and cerebrospinal fluid

Levin¹,

Patlak²

1972

The Journal of Physiology

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SUMMARY1. The kinetics of 24Na exchange in rat cerebrospinal fluid, brain and sciatic nerve were studied during steady-state plasma isotope conditions. The entrance of 24Na into brain and sciatic nerve was found to fit a three compartmental model. Using newly derived equations for compartmental analysis, the first compartment 24Na space of brain was found to be about 22 % and the second compartment space about 6 %; the corresponding sciatic nerve spaces were 26 and 11 %, respectively. In the discussion, arguments are presented that suggest that the first compartment is the extracellular space (ECS) and the second compartment is the intracellular space. The tj for compartmental equilibration between plasma and brain ECS was 2 hr and from ECS to intracellular space 14 hr; in nerve the respective ti's were i hr and 10 hr.2. A third compartment of 18 % was found in sciatic nerve which was interpreted to be anatomically confined to the epi-and perineurium; in brain the corresponding space was 2 % and was felt to be anatomically and kinetically an inactive closed compartment in parallel with the blood.3. There were two tj's for plasma-c.s.f. 24Na equilibration of less than 10 min and 2 hr.4. Profiles of brain, from cortex to ventricle, at 6 min, demonstrated a gradient of decreasing 24Na radioactivity from ventricle to cortex.

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Kinetics of sodium transfer from blood to brain of the dog

Cited by 7 publications

References 0 publications

The permeation of several materials into the fluids of the rabbit's brain

The permeation of several materials into the fluids of the rabbit's brain

CNS, CSF, and extradural fluid uptake of various hydrophilic materials in the dogfish

A compartmental analysis of ²⁴Na kinetics in rat cerebrum, sciatic nerve and cerebrospinal fluid

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Kinetics of sodium transfer from blood to brain of the dog

Cited by 7 publications

References 0 publications

The permeation of several materials into the fluids of the rabbit's brain

The permeation of several materials into the fluids of the rabbit's brain

CNS, CSF, and extradural fluid uptake of various hydrophilic materials in the dogfish

A compartmental analysis of 24Na kinetics in rat cerebrum, sciatic nerve and cerebrospinal fluid

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A compartmental analysis of ²⁴Na kinetics in rat cerebrum, sciatic nerve and cerebrospinal fluid