Ultrastructural reorganizations in the rat cerebral cortex after injection of ascorbic acid into the ventricular fluid.

Abstract

A brief increase in the ascorbic acid concentration in the rat cerebral cortex after intraventricular bilateral injection of 20 microliters of a 0.1% or 1% ascorbic acid solution and also intracisternal injection of 20 microliters of a 0.5% solution results in a prolonged (not less than 21 days) ultrastructural reorganization in the nucleus and cytoplasm of the cortical neurons: the amount of lysosomes, polysomes, vesicles of the Golgi complex, and subsurface cisterns increases, this demonstrating an increasing RNA and protein synthesis, catabolic processes, and neuronal-glial interaction. Changes in the ultrastructure of the synaptic terminals, such as disintegrating mitochondria, formation of myelin-like bodies, and, in addition, after interstitial injection, protrusions into the adjacent dendrite, demonstrate that synapses are one of the sites where excess ascorbic acid affects the CNS. Over a long period, 3 and 6 months after injection, the changes mentioned are not observed but in the glial processes one can observe vacuoles containing degenerating elements.