Action of 3-isobutyl-1-methylxanthine and prostaglandins D2 and E1 on histamine release from rat and guinea pig mast cells.

The action of three compounds reported to elevate intracellular cyclic adenosine monophosphate (cAMP) namely 3-isobutyl-1-methylxanthine (IBMX) and prostaglandins D2 and E1 (PGD2 and PGE1), on histamine release was examined. Three test systems were used: (i) the perfused ovalbumin-sensitized guinea pig lung and (ii) isolated cells from ovalbumin-sensitized guinea pig lung, both of which are IgG-mediated models of anaphylaxis, and (iii) an IgE model of anaphylaxis, using isolated rat peritoneal mast cells from sensitized rats. Both PGD2 and PGE1 were without effect at concentrations likely to be found during anaphylaxis. In contrast, the phosphodiesterase inhibitor, IBMX, was highly active in all three test systems. The role of raised intracellular cAMP levels in the inhibition of histamine release is discussed.