Inhibitory effect of an anti-lipoxygenase agent on immunoglobulin G-mediated anaphylactic contraction of single smooth muscle cells.

Intracellular signal transduction during anaphylactic contractions of smooth muscle and the site of signal generation, or antigen-antibody reaction, participating in the appearance of these contractions were studied. The taenia coli was removed from a guinea-pig which had previously been sensitized with anti-egg albumin (EA) rabbit serum or anti-EA rabbit immunoglobulin G (IgG) fraction. Dispersed smooth muscle cells, obtained after enzymatic digestion, were used as the specimen. The dispersed single smooth muscle cells sensitized with anti-EA rabbit IgG fraction showed anaphylactic contractions in response to antigen administration. The method using enzyme-linked antibody revealed binding of IgG by these single muscle cells. Anaphylactic contractions of the single cells were not inhibited by antihistamines or anti-5-hydroxy-tryptamine (5HT) agents, but they were suppressed by Y-19,432 [1-butyl-5-hydroxy-2-methyl-N-[1-(2-phenylethyl)-4-piperidyl] indole-3-carboxamide hydrochloride hydrate], an inhibitor of 5-lipoxygenase. The anaphylactic contractions of the single smooth muscle cells of the guinea-pig taenia coli appear to be initiated in response to IgG binding with the antigen bound to the smooth muscle plasma membrane. For contraction development, the lipoxygenase pathway was shown to participate as a part of the intracellular signal transduction.