Histamine release and pain production by xanthosine and related compounds

Abstract

Xanthosine (5 to 50 mug.) caused pain on intradermal injection in all human subjects tested: in about half the subjects it also gave a flare. Inosinic acid, uric acid, allantoin, alloxan and theophylline caused pain, but not a flare by intradermal injection in man. Xanthine caused both pain and flare. A number of related compounds in similar doses caused neither pain nor flare. Inosine, inosinic acid, and guanosine, but not xanthosine, were powerful histamine liberators in animals. The lowering of the cat blood pressure, depression of the activity of the guinea-pig ileum and stimulation of guinea-pig uterus by adenosine were confirmed.