STUDIES ON THE PHOSPHORUS METABOLISM IN THE CENTRAL.PATHWAY OF THE COCHLEAR NERVE

Abstract

P32 metabolism in the central pathway of the cochlear nerve of the rat was examined to study one aspect of dynamic biochemistry of nerve fissue, and also biochemical mechanism in the phys- iology of audition. Normally, the quantity of P32 which was transferred into the tissue of the central nervous system was quite small. P32 was transferred first to the acid soluble phosphorus fraction and them to nucleic acid protein fraction. The transfer to the lipoid fraction was, though it took place last, greatest in quantity. An experiment with 5, 000 cps pure tone of 110 phon revealed that the transfer of P32 to the nucleic acid protein of the central pathway of the cochlear nerve was enhanced by a brief stim- ulation and suppressed by a long lasting stimulation. This phenomenon was especially remarkable-in in the lower terminal nucleus. By the administration of Dihydrostreptomycin the transfer of P32 to nucleic acid protein was inhibited. To reproduce these in vivo findings appropriately in vitro, the experiment of P32 transfer was made, by measuring oxygen consumption with the Warburg apparatus. The P32 metabolism sho- wed the same tendency both in vivo and in vitro. In this in vitro experiment, . by addition of vit- amin A or ATP preparation, the transfer of P3 to the nucleic acid of the central pathway of the- cochlear nerve was enhanced. In the nervous tissue in which carbohydrate metabolism plays a most important role, the metabolism of phosphorus seems to be essential to maintain its function.