Uridine and other nucleic acids form part of RNA, DNA, coenzymes, second messengers, etc. Uridine uptake in nerve cells is an expression of neuronal RNA synthesis. More knowledge of uridine functions in neurones may give a better understanding of mechanisms underlying dementia, and they could be useful in treating brain tumors. Pakkenberg and co‐workers have studied the uridine uptake in the brains of mice and monkeys under various conditions (after hypoxia, after carbon‐dioxide treatment, after MPTP treatment, after electrostimulation, etc.) and the results are correlated with other biological brain paramet