Among the many pharmacologic effects of histamine, its ability to stimulate gastric secretion has found widest clinical application. The routine subcutaneous administration of this drug as a test for achlorhydria, however, has certain disadvantages. In ordinary doses it frequently produces flushing, palpitation, headache, and even vomiting. In larger doses or in hypersensitive persons, shock may supervene. It is therefore of interest to note that a new analog of histamine has been discovered that is reported to stimulate gastric secretion without producing any of these unpleasant side effects.
This compound, 3-(β ethylamine) pyrazole, an isomer of histamine in which the heterocyclic ring has a pyrazole instead of an imidazole configuration, was first synthesized and studied by Lee and Jones,1 who observed that, unlike histamine, it did not cause contraction of the isolated guinea pig ileum or lower the blood pressure of the anesthetized cat. Subsequently, Rosiere and Grossman2 demonstrated