Accumulation of [ 3H]lysine in various types of neurons in male rats

Abstract

[ 3H]lysine injected intravenously into male rats was observed to accumulate in various neurons at levels which were significantly higher than that observed in the plasma or spinal cord grey matter. While neurons, grey matter and dorsal root ganglia demonstrated an early period of rapid accumulation of lysine after injection, the neurons were characterized by having a short period of declining radioactivity levels after attaining their early peak level. This declining phase was then followed by a second period of accumulation. Although the curves reflecting accumulation into the different neuronal types (spinal cord, ventral horn cells, dorsal root ganglion cells and Purkinje cells) were similar, the total amounts of 3H activity (chromatographically lysine) in the different neuronal types were in most instances significantly different from each other. Finally, a comparison of the amount of lysine accumulated in the neurons of the central and peripheral nervous systems indicated that there are no significant differences in the amount of lysine accumulated which could be related to the presence or absence of a blood-brain barrier.