Movement of Sodium-22, Radioiodinated Protein, and Tritiated Water from the Cisterna Magna into the Cerebrovascular Circulation

A SWEET 1 and m a n y others have emphasized, a lmost all substances in the cerebrospinal fluid (CSF) are capable of m o v e m e n t across any of the melnbranes in the central nervous system (CNS), and the concept t ha t CSF is absorbed via the arachnoidal villi or by blood vessels is oversimplified. T h e major research problem is to delineate the pa t te rns of movement of the various const i tuents of the CSF. Since the dynamic na ture of the cerebrospinal fluid-brain barr ier varies with location, species, 9 age, 1~ and physiological state, 6 the problem is a difficult one. We are reporting a s tudy on the absorpt ion of tr i t iated water, radioactive sodium ion, and radioiodinated protein from the cisterna magna of monkeys in an a t t e m p t to view the separate movement of three dist inct ly different CSF components as an equilibrium is established between the CSF and the blood.