Mechanisms Controlling Hemolymph Circulation Under Resting Conditions In The Chagas Disease Vector Rhodnius prolixus (Stal)

Abstract

Chagas disease vectors can ingest several times its own volume in blood with each meal. This ad libitum feeding causes an intense process of diuresis inducing the insect to eliminate a large quantity of urine during the next few hours. This process, which is under the control of endocrine and neuroendocrine systems is necessary to restore homeostasis, and to begin physiological mechanisms leading to growth and reproduction. To ensure diuresis, the speed of circulation of the hemolymph must be increased to allow the Malpighian tubules to produce the urine. Behind this acute phenomenon, triatominae insects can spend several weeks without feeding. In this way, it could be assumed that during most of the time of life the insect is in a resting condition. Triatominae circulatory system is quite simple, including a dorsal vessel which pumps hemolymph in an anterograde direction. The return is caused by peristaltic contractions of the anterior midgut. While the mechanisms controlling the circulation of the hemolymph during post-prandial diuresis was largely analysed, the mechanisms controlling it during resting conditions is poorly understood. In this study we analyse several canonical pathways (i.e. L-type VGCC; GPCR; RyR; IP3R) and a novel system represented by the recently characterized Piezo proteins. Our results show that during the resting condition hemolymph circulation depends on a cross-talk between myogenic activity, inhibitory and stimulatory cell messengers, and also Piezo proteins. We present for the first time the existence of a putative Piezo protein in Hemiptera.