Histamine H-1 receptors on rat peritoneal mast cells

In order to characterize the receptor subtype involved in histamine stimulation of increased cyclic AMP levels in rat mast cells with consequent impairment of anaphylactically induced mediator release, the binding of the H-1 receptor antagonist [3H]pyrilamine to mast cells was examined. Pyrilamine bound rapidly, in a saturable and reversible fashion, and with increased binding at 4 degrees C as compared with 21 degrees C and 37 degrees C. [3H]Pyrilamine binding was displaced by H-1 antagonists (tripelennamine greater than pyrilamine greater than or equal to diphenhydramine) greater than histamine greater than the H-2 antagonist, cimetidine. H-1 agonists displaced pyrilamine binding less efficiently than histamine but better than H-2 agonists. Rat mast cells have a single homogeneous population of low affinity (KD = 222 +/- 33 nM) H-1 receptors with a Bmax of 9.7 +/- 2.3 pm/10(6) mast cells and 5.4 +/- 0.92 x 10(6) binding sites per mast cell. Thus, the mast cell has an H-1 type histamine receptor which is probably involved in histamine-induced cyclic AMP increases.