The molecular characterization of the kinin transcript and the physiological effects of kinins in the blood-gorging insect, Rhodnius prolixus

The dramatic feeding-related activities of the Chagas' disease vector, Rhodnius prolixus are under the neurohormonal regulation of serotonin and various neuropeptides. One such family of neuropeptides, the insect kinins, possess diuretic, digestive and myotropic activities in many insects. In this study, we have cloned and examined the spatial expression of the R. prolixus kinin (Rhopr-kinin) transcript. In addition, in situ hybridization has been used to map the distribution of neurons expressing the kinin transcript. Physiological bioassays demonstrate the myostimulatory effects of selected Rhopr-kinin peptides and also illustrate the augmented responses of hindgut contractions to co-application of Rhopr-kinin and a R. prolixus diuretic hormone. Two synthetic kinin analogs have also been examined on the hindgut. These reveal interesting properties including a relatively irreversible effect on hindgut contractions and activity at very low concentrations.