Allergic reactions,cyclic AMP and histamine release

Summary Both isobutylmethylxantine and theophylline increased the level of cyclic AMP in the mast cell. Theophylline reduced the allergic histamine release, whereas isobutylmethylxynthine caused a pronounced potentiation of the histamine release. This indicates that the hypothesis of an inverse relationship between the level of cyclic AMP in mast cells and histamine release is too simple.This work was supported by grants from the Danish Medical Research Council (Grant No. 512-5270) and from Lundbeckfonden.     

Flavonoid compounds are potent inhibitors of cyclic AMP phosphodiesterase.

The inhibitory activity of 19 flavonoid molecules on cyclic AMP breakdown by a commercial beef heart phosphodiesterase preparation is reported. 7 compounds are active in the micromolar range, 2 of which have a potency equivalent to that of papaverine. Some structure activity relationships are drawn.     

Action of histamine and vasoactive intestinal peptide (VIP), on cyclic AMP in gastric glands isolated from human fetal stomach

Summary Histamine and VIP produce an elevation of cAMP production in gastric glands isolated from the human fetal stomach at 15 weeks of gestation. These effects were attributed to the activation of 2 distinct receptor-cAMP systems, one being sensitive to histamine in parietal cells, and the other being sensitive to VIP in muco-peptic cell populations. The results suggest that histamine and VIP may play a role in inducing gastric secretion during fetal life in man.     

Action of histamine and vasoactive intestinal peptide (VIP) on cyclic AMP in gastric glands isolated from human fetal stomach

Histamine and VIP produce an elevation of cAMP production in gastric glands isolated from the human fetal stomach at 15 weeks gestation. These effects were attributed to the activation of 2 distinct receptor-cAMP systems, one being sensitive to histamine in parietal cells, and the other being sensitive to VIP in muco-peptic cell populations. The results suggest that histamine and VIP may play a role in inducing gastric secretion during fetal life in man.     

Circadian variation of adrenocortical cyclic nucleotides (cyclic AMP and cyclic GMP) in hypophysectomized rats

The existence of a circadian variation in the adrenocortical concentrations of cyclic AMP and cyclic GMP in male adult Wistar rats examined 10 days after hypophysectomy is demonstrated. The results suggest that the circadian variations of adrenocortical cyclic nucleotides observed previously in intact rats might not entirely depend upon pituitary corticotrophin.     

Circadian variation of adrenocortical cyclic nucleotides (cyclic AMP and cyclic GMP) in hypophysectomized rats

Summary The existence of a circadian variation in the adrenocortical concentrations of cyclic AMP and cyclic GMP in male adult Wistar rats examined 10 days after hypophysectomy is demonstrated. The results suggest that the circadian variations of adrenocortical cyclic nucleotides observed previously in intact rats might not entirely depend upon pituitary corticotrophin.Acknowledgment. Thanks are due to Prof. J. M. Racadot and Dr Y. Drouet for their assistance with the histological examinations.     

Effect of cyclic AMP and theophylline on phagocytotic activity of Tetrahymena pyriformis.

Dibutyril cAMP and the cPDE-inhibitor theophylline both enhance the phagocytotic activity of Tetrahymena. Theophylline and cAMP-activating histamine are synergistic. It follows that the cAMP-adenylcyclase system functions in the unicellular animal Tetrahymena.