Distribution, Exchange and Migration of Phosphate Compounds in the Nervous System

Abstract

The total P of guinea pig brain, cord, and nerve has been detd. chemically (Schneider method) in the fractions: acid-soluble P, phospholipid P, nucleoprotein P, and phosphoprotein P (probably inositol diphosphate in brain). Absolute amts. of these fractions are given. Following intraperit. P32 injn. in single or daily (up to 14) doses, the specific activities of these same fractions (and of plasma acid soluble P) have been detd. at intervals up to 36 days after the final injn. Tables and curves present the time course of activity rise and fall, and regression lines indicate exchange rates of the fractions. Both diffusion of P from plasma to cells and uptake of inorganic P into organic combination are slow, even diffusion equilibrium requiring over 10 days. Some theoretical expectations and exptl. divergencies are discussed. Malononitrile produced no change in amt. or exchange rate of nucleoprotein or other fraction. Nerve section led to a halving of phospholipin and doubling of nucleoprotein in nerve and to a sharp increase in exchange rates[long dash]up to tripling (vs. control) of the nucleoprotein specific activity. Activities of cord were also, though less markedly, increased. An anticipated peripherad flow of nucleoprotein along nerve fibers was not revealed by these expts. Phosphoprotein, however, was found to flow peripherad at a rate of about 3 mm. a day. A theoretical treatment of precursor-product relations, by J. Z. Hearon is appended.