Effect of lowering the peripheral level of 5-hydroxytryptamine in host on the virulence of Entamoeba histolytica

Abstract

To ascertain the effect of lowering the peripheral 5-hydroxytryptamine (5-HT) level in the host on the pathogenesis of E. histolytica, p-chlorophenylalanine, a 5-HT synthesis blocker was used. Just weaned albino rats of Charles-Foster strain as the experimental animals and caecal scoring of Neal were used to quantitate the pathogenicity. When infected animals were treated with p-chlorophenylalanine, the caecal scores of all the five strains tested were reduced significantly compared to untreated control animals. Thus lowering of peripheral 5-HT level in the host, decreased the pathogenicity of E. histolytica. Based on these results as also our earlier finding that an increase in peripheral 5-HT level enhances the pathogenicity of the parasite, it is proposed that peripheral 5-HT level is an important host factor modulating the virulence of E. histolytica.