[The effect of serotonin on the functional activity of monocytes].

The treatment of human peripheral blood monocytes with serotonin at concentrations 10(-3) and 10(-5) M over 20 minutes decreases a zymosan-induced luminol-dependent chemiluminescence of cells, whereas a 5 minutes treatment with serotonin at the concentration of 10(-5) M increases the chemoluminescence. The correlated change in monocyte capacity of secreting hydrogen peroxide has been registered. Serotonin activates, to a little extent, the monocyte capacity of phagocytizing the opsonised sheep erythrocyte. The maximum increase (2-3 times) of intracellular cAMP content and the decrease in cytosol cAMP-binding capacity are registered after a 5 minutes incubation. The lowering of the share of irreversibly bound in vitro cAMP under the influence of serotonin may suggest a preferable binding of cyclic nucleotide in vivo by regulatory subunits of cAMP-dependent protein kinase I.