Hymenopteran Venom Stimulates Adenylate Cyclase in Cultured Human Cells through a Histamine Receptor

Abstract

We have examined the effect of venom sac extract (VSE), prepared from two hymenopteran species, on intracellular cyclic AMP (cAMP) accumulation in a cultured human cell line. VSE prepared from the oriental hornet (Vespa orientalis) and from the paper wasp (Polistes Carolina) induced an increase in accumulation of cAMP in human, transformed, non-pigmented, ciliary epithelial cells. The effect of V. orientalis VSE on intracellular cAMP was dose-dependent. Blocking the response of adenylate cyclase-linked β-adrenergic receptors was without effect on this cellular response to VSE. On the other hand, the response to VSE prepared from both species was suppressed almost totally by the H₂-histamine receptor-specific antagonist, cimetidine. The findings are discussed in the light of earlier observations that described a significant reduction in intraocular pressure in vertebrate animals treated with V orientalis VSE.