It has been known from previous experiments2 that various portions of the brain exchange radioactive phosphate with the plasma at greatly different rates. The fastest exchange was observed in the superficial layers of the cortex and in the ventricular lining. This was explained by the proximity of cerebrospinal fluid, which acted as an intermediary in the transport of P32 from plasma to brain. Nevertheless, the great number of capillaries in the cortex as compared with that in the white matter could not be disregarded as a factor contributing to the increased rate of phosphate exchange. It has also been considered16 that the presence of blood in these capillaries misleadingly increases the P32 concentration of the tissue specimen in experiments of short duration when the specific activity of the blood is still considerably higher than that of the brain.
Material and Methods
The experiments were performed on
BAKAY L. Relationship Between Cerebral Vascularity and P32 Uptake. AMA Arch NeurPsych. 1957;78(1):29-36. doi:10.1001/archneurpsyc.1957.02330370043003