[Functional-metabolic changes in the brain during various conditions of supplying the rat with vitamin PP]

Content of nicotinamide nucleotides, reception of NAD by synaptic membranes and the system of 14C-serotonin uptake and liberation in rat brain nerve endings were studied under various conditions of vitamin PP consumption. In PP hypovitaminosis binding of 14C-NAD was decreased in synaptic membranes as a result of alterations in capacity of receptor sites, which occurred simultaneously with low level of nicotinamide coenzymes in rat brain. These alterations led to deterioration of NAD modulating function in liberation of 14C-serotonin from synaptosomes. The data obtained suggest that functional activity of NAD-receptor system in synaptic membranes of rat brain depends on the rate of vitamin PP consumption. These results might be considered in clinical research when vitamin PP is used for treatment of various diseases.