H₂-receptors in peripheral blood vessels

Abstract

THE recent observation that certain histamine responses which were resistant to antihistaminic blockade may now be abolished by the newly synthesised compounds burimamide (N-methyl-N¹ [4-(4/5)-imidasolyl) butyl] thiourea) and metiamide (N-methyl-N¹ [2/(5 methylimidazol-4-yl) methylthio/ethyl] thiourea) (both compounds, Smith, Kline and French) has culminated in the interpretation of histamine action in terms of both H₁-and H₂-receptors¹. Until now the attention of workers in this field has centred upon gastric acid secretion. Our own studies, however, have been directed at the receptor control of the microcirculation and we have previously reported failure of conventional antihistaminics to block histamine responses in our experimental model². Here we report results obtained in the canine diarthrodial joint which demonstrate the abolition of histamine responses by H₂ and not by H₁-bloeking compounds and thus supporting the conclusion that H₂-receptors are involved in the control of peripheral blood vessels.