Active transport out of CSF has been described for several compounds and is considered to be one of the homeostatic mechanisms by which a tight regulation of the brain extracellular composition is maintained. Considerable interest has therefore centered on defining the mechanisms and sites of CSF transport. In the case of amino acids, the presence of a carrier mediated and energy dependent transport from ventricular CSF was shown and in vitro experiments established a role in this process for the choroid plexus, which showed a concentrative uptake of amino acids. An important extension of this concept was provided by the demonstration of mediated clearance of amino acids from the extraventricular CSF of the spinal and cranial subarachnoid compartments. Since these compartments lack choroid plexus, these observations indicated that other cell types may be sites for the transport of amino acids from CSF. The present study sought to establish whether the meningeal membranes might be such a locus: adult mongrel dogs were used for the experiment. Although the authors found an accumulation of AIB by meninges to be less by 2.6 fold than that of choroid plexus on a unit weight basis, the accumulation of solute by available sites in the total meningeal surface may exceed (considerably) that occurring across choroidal epithelium. The mechanism for removal of the accumulated solute from the meninges is uncertain, but may involve clearance by pial blood vessels.
|Original language||English (US)|
|Number of pages||3|
|Journal||Journal of Neurochemistry|
|State||Published - 1975|
ASJC Scopus subject areas
- Cellular and Molecular Neuroscience