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

NATALIA CAPRIOTTI; JUAN IANOWSKI; ONS SHEILA

Congreso; Congreso de la Sociedad Argentina de Investigación en Neurociencias; 2020

Given that hematophagous insects ingest large quantities of blood in a single meal, they must undergo a rapid post-prandial diuresis in order to maintain homeostasis. In the kissing bug Rhodnius prolixus (Hemiptera: Reduviidae), the coordinated activity of the Malpighian tubules and anterior midgut maintains water and ion balance during the post-prandial diuresis. Three to four hours after the meal the diuretic process finishes, and the animal enters an antidiuretic state to ensure water conservation until the next blood intake. The diuretic and antidiuretic processes are tightly regulated by serotonin and neuropeptides in this insect. In this work, we report that the neuropeptide precursor CCHamide is involved in the regulation of the post-prandial diuresis in the kissing bug Rhodnius prolixus. Our results suggest a dual effect of RhoprCCHamide peptides, enhancing the serotonin-induced secretion by Malpighian tubules, and inhibiting serotonin-induced absorption across the anterior midgut. To our knowledge, this is the first report of a hormone presenting opposite effects in the two osmoregulatory organs (i.e. midgut and Malpighian tubules) in the insects, probably reflecting the importance of a well-tuned diuretic process in hematophagous insects during different moments after the blood meal.