Effect of stimulation of dopamine and histamine receptors on spontaneous lymphocyte adhesion in vitro

With the help of spontaneous lymphocyte adhesion test the influence of dopamine and histamine on the adhesion of peripheral blood lymphocytes has been studied in healthy donors. It was shown that dopamine enhanced spontaneous lymphocyte adhesion, with the optimal concentrations of the substance for the realization of a stimulating effect being 10(-4)-10(-6) M. The effect of the enhancement was pharmacologically specific, as it was completely blocked by dopamine receptor-blocker--haloperidol. It was demonstrated that low concentrations of histamine (10(-7)-10(-8) M) enhanced, while higher concentrations (10(-6)-10(-3) M) inhibited lymphocyte adhesion. Dimedrol, but not cimetidine abolished the enhancement of spontaneous lymphocyte adhesion, while the adhesion inhibition was blocked by cimetidine, but not dimedrol. Thus, the revealed histaminergic enhancement and inhibition of spontaneous lymphocyte adhesion is mediated through the influence of histamine on H1- and H2-receptors, respectively.