Composition of fluid obtained from choroid plexus tissue isolated in a chamber in situ*

Abstract

SUMMARY1. A method was developed for isolating a segment of the choroid plexus of the lateral ventricle of the cat brain in a chamber in situ.2. A comparison of electrolyte and protein concentrations in serum, ultrafiltrate of serum, cisterna magna fluid, fluid accumulated in the chamber and fluid collected from the choroid plexus by another technique, demonstrates that the chamber fluid is a secretary product of the choroid plexus.3. The rate of fluid formation in the chamber was 0 4 10. min-mg-' of tissue, a value in good agreement with reports in the literature.4. The observation that the concentration of K+ in choroid plexus fluid was lower than that in the serum ultrafiltrate suggests that K+ is regulated by an active transport process at the choroid plexus.5. Significant correlation was found between electrolyte values and the protein content of the chamber fluid. This suggests that plasma is the probable source of the protein in the chamber fluid and that K+ and probably Ca2+ and Mg2+ in c.s.f. are subject to active homoeostatic regulation by the choroid plexus. 6. The technique described provides a new opportunity to study in detail the functional characteristics of the choroid plexus.

Regulation of cerebrospinal fluid bicarbonate by the cat choroid plexus.

“…greater than that of large cavity c.s.f. (Ames, Sakanoue & Endo, 1964;Miner & Reed, 1972). Analysis of data on the kinetics of labelled bicarbonate movement from blood to c.s.f.…”

“…Body temperature was maintainednear normalwith an electric heating pad. The choroid plexus was isolated in a chamber in situ as described in detail by Miner & Reed (1972). In brief, the method requires an extensive unilateral craniotomy, removal of the cerebral cortex overlying the left lateral ventricle and exposure of the plexus within the lateral ventricle.…”

“…The in 8itU isolated choroid plexus preparation developed by Miner & Reed (1972) provides a unique system in which to study the role of the choroid plexus in the regulation of c.s.f. composition.…”

The effect of lithium on electrolyte transport by the in situ choroid plexus of the cat.

“…production and also participates in regulating the composition of the c.s.f. The in situ isolated choroid plexus preparation developed by Miner & Reed (1972) was used in the present study to investigate the effect of varying the lithium concentration in plasma and in c.s.f. on the distribution of other electrolytes in the c.s.f.…”

Transfer of Magnesium across the Perfused Choroid Plexus of Sheep

“…The foramen of Munro was sealed with tissue glue and the chamber of the ventricle filled with light white oil (M3516, Sigma Chemical Co.). Droplets of fluid emerging from the choroid plexus and accumulating under the oil were collected at intervals in glass micro pipettes as described by Miner and Reed (1972).…”