The neuropeptide RhoprCCHamide2 inhibits serotonin-stimulated transcellular Na+ transport in Rhodnius prolixus.

CAPRIOTTI, NATALIA; IANOWSKI, JUAN P.; ONS SHEILA

Congreso; XXXV Annual Meeting of the Argentinian Society for Neuroscience Research; 2020

Sociedad Argentina de Neurociencias

Rhodnius prolixus is a blood-feeding insect vector of Chagas' disease. During each bloodmeal the animals ingest large volumes of blood, that may be up to 12 times the unfedbody mass. These large blood meals impose a significant osmotic stress for the animalsdue to the hyposmotic condition of the ingested blood compared to the insect'shaemolymph. We investigated the ion transport machinery triggered by stimulation withthe diuretic factor serotonin and the effect of the neuropetide modulatorRhoprCCHamide2. Ussing chamber assays revealed that serotonin-stimulatedtransepithelial short circuit current (Isc) was blocked by treatment with the Na+ channelblocker amiloride or the Na+/K+-ATPase inhibitor ouabain. Incubation in Na+-free, butnot Cl--free saline, blocked the effect of serotonin on Isc. Moreover, treatment withNKCC and NCC blockers had no effect on Isc or fluid secretion. Treatment withneuropeptide RhoprCCHamide2 diminished serotonin-stimulated Isc across the crop.The results suggest that Na+ undergoes active transport via an apical amiloride-sensitiveNa+ channels and a basolateral ouabain-sensitive Na+/K+-ATPase while Cl- istransported through passive paracellular pathway. RhoprCCHamide2 reduces transportby inhibiting transcellular Na+ transport.