Strain differences in concanavalin A- induced paw edema in the rat: Involvement of histamine H1 and H2 receptors

Abstract

The present study tests the hypothesis that the difference in the intensity of paw edema found between the Dark Agouti (DA) and Albino Oxford (AO) rat strains originates from the distinct participation of histamine, serotonin and their corresponding receptors in Concanavalin A (Con A)-induced inflammation. DA and AO male rats were intraplantarly injected with specific receptor antagonists prior to Con A, and the intensity of inflammation was determined by measuring the paw diameter. Our results have showed that histamine H1 and H2 receptor antagonists reduced the Con A-induced paw edema in DA rats, while serotonin 5HT3 receptor antagonist diminished the inflammation in both DA and AO rat strains. The calcium channel blocker did not change Con A-induced inflammation. Strain differences in the intensity and kinetics of inflammation observed between the DA and AO rats are most likely defined by the diversity of mediators released and their receptors activated upon Con A injection.