Histamine Receptors in the Synovial Microcirculation

Abstract

Abstract. This study was designed to investigate the respective roles of H1 and H2 receptors in the control of the microcirculation by examining the effectiveness of the H2 receptor antagonist metiamide (Met.) and Hj receptor antagonist mepyramine is blocking the action of histamine on synovial perfusion. Synovial perfusion was monitored indirectly by calculating the half‐life (T1/2‐ min.) of the clearance rate of 133Xe from canine diarthrodial joints. The 133Xe clearance rate, unaffected by metiamide alone, was consistently increased by histamine alone. Metiamide produced a dose related effect on the histamine response with consistent abolition of response at high dose ratios of metiamide t..