We studied the effect of UV light (240-390 nm) in doses of 75.5-4530 J/m(2) on functional properties and level of intracellular messengers (cAMP, Ca(2+), NO) in lymphocytic cells of the peripheral blood. Correcting effects of UV light in a dose of 151 J/m(2) on cytotoxic activity of lymphocytes against Ehrlich ascetic carcinoma and calcium concentration in lymphocyte cytosol were observed. We found that UV light reduces the cAMP content and increases NO concentration (151-4530 J/m(2)) in photomodified cells. The involvement of adenylate cyclase and phosphoinositide signaling pathway into the mechanisms of modulation of functional properties of lymphocytes after exposure to UV light was demonstrated.