Aspects of the control of diuresis in the blood gorging insect, Rhodnius prolixus

Post-feeding diuresis in Rhodnius prolixus is neurohormonally controlled by serotonin and at least one peptidergic diuretic hormone (possibly a CRF-related peptide). These appear to be released by two different neurosecretory groups – 5 dorsal unpaired median (DUM) cells and 5-6 lateral neurosecretory cells of the mesothoracic ganglionic mass. The DUM cells co-localize serotonin and the calcitonin-related peptide RhoprDH31. The lateral neurosecretory cells co-localize a CRF-related peptide and a kinin-like peptide. Serotonin and the CRF-related peptide, ZooneDH, each stimulate maximum secretion by the upper Malpighian tubules, whereas only serotonin stimulates KCl reabsorption from the lower Malpighian tubules. RhoprDH31 is only weakly diuretic and Leucokinin 1 has no diuretic activity. Neither stimulates KCl reabsorption. The possible role for multiple diuretic hormones and for co-localization of diuretic factors is discussed