[The effect of nitroglycerin on the Ca2+ ion level in the cytoplasm of human lymphocytes]

Fluorescence was used to examine the effects of nitroglycerin (60 microM) on basal and mitogen-induced (ConA, 25 micrograms/ml) Ca2+ levels in the human lymphocytic cytoplasm. Calcium-blocking effect of nitroglycerin was markedly shown in the medium containing 1 mM CaCl2 and virtually absent in calcium-free buffer. It is concluded that nitroglycerin affects cellular Ca2+ entry. A 120-minute preincubation led to a complete loss of the inhibitory effects of the drug on mitogen-induced Ca2+ responses of lymphocytes. Human lymphocytes are proposed as an experimental model for investigating the effects of nitrates and the mechanisms of their tolerance development.