Effects of antiallergic drugs on cyclic nucleotides in guinea pig ileum and trachea.

In former papers we have provided evidence on the protective effect of disodium cromoglycate (DSCG) and ketotifen (Ke) against the contractions induced by various agonists (histamine, serotonin, acetylcholine, prostaglandins) in ileal and tracheal smooth muscle of guinea pigs. To offer an insight into the mode of action of these antiallergic drugs we quantified concentrations of cyclic AMP and GMP in these tissues. We observed that DSCG (10(-3)-10(-2) M) significantly diminished the concentration of cyclic AMP in ileum and trachea of guinea pigs, but it increased the level of cyclic GMP in ileum. Ketotifen (10(-6)-10(-4) M) does not modify cAMP and cGMP in ileum, however, in trachea it significantly decreases the concentrations of cGMP. We also studied the effects of oxatomide, ICI 74.917 and BRL 10.833 on cyclic nucleotides concentrations in guinea pig ileum BRL 10.833 increases cAMP at a relatively high dose (10(-4) M). ICI 74.917 at the same dose decreases cGMP. Oxatomide (10(-6)-10(-4) M) does not modify concentrations of both nucleotides. Our results demonstrate that these antiallergic drugs do not have a unique effect on cyclic nucleotides. Our findings do not support a relevant role of these nucleotides on the mechanism of action of these antiallergic drugs.