<prompt> The first H2 receptor blocker was synthesized in 1972 byAsch and ChildSir James BlackGaddum and PicarelliVane  <response>: Sir James Black. He synthesized the first H2 blocker burimamide; and subsequently cimetidine.Asch and Child classified histamine receptors into H1 and H2.Gaddum and Picarelli classified serotonin receptors into D type and M type.Vane observed that aspirin acts by inhibiting PG synthesis. 