The first H2 receptor blocker was synthesized in 1972 by –

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.