A species comparison of the histamine H2-receptor on mast cells and basophils

The histamine H2-agonist dimaprit was employed in experiments to investigate the role of H2-receptors in mediator release systems from the rat, guinea-pig and man. Whereas inhibition of histamine release by dimaprit was observed in all 3 species, this effect appeared not always to be related to H2-receptor occupancy. Although the data in general support previous evidence for the presence of H2-receptors on human basophils and guinea-pig mast cells, the use of dimaprit as a pure H2-agonist in these studies is questioned. No evidence for H2-receptors on rat mast cells was obtained.