Histamine H2 Receptor‐Mediated Cyclic AMP Formation in Human Platelets

Abstract
The influence of histamine on the level of cyclic[c]AMP was studied in human platelets. A dose-related accumulation of cAMP was obtained, culminating at about 10 .mu.M of histamine. The response was blocked by the H2 antagonist cimetidine, but neither by H1 antagonists nor by .alpha.- or .beta.-adrenergic antagonists. The results suggest that histamine causes an accumulation of cAMP in human platelets by stimulation of H2 receptors. cAMP accumulation is supposed to be associated with a depression of the platelet function, and a reduced platelet release reaction was actually demonstrated by our results.