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Updated: Jul 20, 2026
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A Rapid and Specific Microplate Assay for the Determination of Intra- and Extracellular Ascorbate in Cultured Cells
Published on: April 11, 2014
The influx of ascorbic acid into the rat's brain
Summary
Ascorbic acid (vitamin C) enters the rat brain via cerebral capillaries through both carrier-mediated transport and simple diffusion. Cerebral capillaries are the primary pathway for vitamin C brain entry.
Area of Science:
- Neuroscience
- Biochemistry
- Physiology
Background:
- Ascorbic acid (vitamin C) is essential for brain function.
- Understanding its transport into the brain is crucial for neurological health.
- Cerebral capillaries play a key role in the blood-brain barrier.
Purpose of the Study:
- To quantify the transport of ascorbic acid into the rat brain.
- To differentiate between carrier-mediated and diffusional transport mechanisms.
- To determine the contribution of cerebral capillaries to vitamin C brain uptake.
Main Methods:
- Utilized the steady-state initial-rate technique to measure [14C]ascorbic acid influx.
- Analyzed transport kinetics to identify carrier-mediated and diffusion components.
- Calculated kinetic parameters (Vmax, Kt, Kd) for each transport mechanism.
Main Results:
- Ascorbic acid transport into the brain occurs via both carrier-mediated and simple diffusion processes.
- The carrier system exhibited an apparent Vmax of 1.2 nmol/min/g and a Kt of 125 microM.
- The diffusional component had an apparent transfer constant (Kd) of 0.98 microliter/min/g.
Conclusions:
- Cerebral capillaries are the predominant route for ascorbic acid entry into the brain.
- Both active transport and passive diffusion contribute to vitamin C brain levels.
- These findings highlight the critical role of cerebral capillaries in brain nutrition.
