“…In 1975, Lindberg et al, in Sweden, and Hatfield and Schaumberg, in the United States, published almost simultaneously the isolation and the chemical structure of the active principle-coprine-pointing out that this compound was not active in vitro, hence suggesting that the effector is not coprine itself but rather a metabolite. Later, Vanhaelen et al [1976] isolated a biologically active compound which sensitized mice to alcohol, its chemical properties resembling those of oligopeptides, aminoacids, or amines like tryptamine. These additional data, although incomplete, reinforced the preceding results.…”