[Effect of nicotinamide adenine dinucleotide on the serotoninergic mediator system in the rat brain during 3-acetylpyridine administration].

The effect of administration of 3-acetylpyridine (antivitamin B3), on rat brain serotoninergic and NAD receptor systems was investigated. The injection of 3-acetylpyridine to rats caused a decrease of NAD and serotonin content in the brain and changes in [U-14C]NAD binding to synaptic membranes, serotonin uptake by nerve endings, as well as sensitivity of this process to NAD (10-5 M). Pretreatment of animals with nicotinamide restored modulating effect of NAD.

[Interaction of GABA-ergic component of NAD with benzodiazepine receptors during epileptogenesis].

Nitrozepam has been shown to decrease specific binding of [14C]NAD by the synaptic mem-branes approximately by 40%. Alongside with the latter GABA in the concentration of 10(-5) M potentiates the effect observed. Blocking in vitro of GABA receptors by bicuculin removes both the tranquilizer and GABA effect.

[NAD-metabolizing capacity of Saccharomyces cerevisiae mutants].

The activity of the key enzymes of the salvage synthesis and degradation of NAD (nicotinic acid mononucleotide pyrophosphorylase and NAD glycohydrolase) was studied in Saccharomyces cerevisiae mutants selected earlier as potential producers of NAD. An enhanced NAD-producing ability of the mutants was shown to be related to their reduced NAD-degrading activity: thus, NAD glycohydrolase in mutants 110, 118, and 206 was inactive in all growth phases regardless of the level of NAD biosynthesis.

[The functional characteristics of the inhibitory mediator systems in the brain synaptosomes of PP vitamin-deficient rats].

A decrease of the NAD and serotonin level in the brain of rats with PP hypovitaminosis is shown. NAD in concentration of 10(-6) M in vitro exerts a less pronounced inhibiting influence on the neuronal uptake of [14C]serotonin and [14C]GABA by brain synaptosomes of rats with PP hypovitaminosis. GABA content under such conditions increases as compared with the control and correlates with changes in the [14C]GABA uptake system.