Resting Metabolism of Immature Nerve Fibers in the Developing Chick

Abstract

In peripheral nerve excised from incubating chicks, the resting oxygen utilization per unit weight of axons and their supporting elements has been found to decrease during their development into the adult form. There is an inverse relation between the relative length of the internodes of the fibers within a nerve trunk and its resting metabolism. The relative length of the internodes or of the trunk is a direct function of the femur length of the animal. As nerve fibers elongate, they distribute their energy consuming processes more efficiently with the result that there is a lower overall expenditure per unit of weight. If the resting respiration of the axoplasm and membrane is high relative to the supporting elements, these findings suggest that in nerve fibers metabolic processes, like excitatory processes may be confined to the nodes of Ranvier.