[Frontiers in Bioscience E1, 250-262, June 1, 2009]

Peptides and serotonin control feeding-related events in Rhodnius prolixus

Ian Orchard

Department of Biology, University of Toronto Mississauga, Mississauga, ON, L5L 1C6, Canada


1. Abstract
2. Introduction
3. Distribution of diuretic hormones
3.1. Immunohistochemistry
3.2. Circulating Neurohormones
4. Neurohormonal control of diuresis
4.1. Control of fluid absorption by anterior midgut
4.2. Control of fluid secretion by upper Malpighian tubules
4.3. Control of KCl reabsorption by lower Malpighian tubules
4.4. Synergism between diuretic hormones
4.5. Termination of diuresis
5. Diuretic hormones and other feeding-related events
5.1. Salivary glands
5.2. Epidermis
5.3. Anterior midgut
5.4. Hindgut
6. Perspectives
7. Acknowledgements
8. References


Rhodnius prolixus periodically gorges on a blood meal that could compromise salt and water balance. This, however, is prevented by rapid production of urine within minutes of feeding. The Malpighian tubules increase their rate of secretion 1,000 fold leading to the production of a hypo-osmotic urine that is high in NaCl content. Feeding and post-prandial diuresis in R. prolixus are tightly coordinated events, involving a variety of neurons within the central nervous system. The present review considers how neurohormones provide flexibility in signaling for the maintenance of hemolymph homeostasis in response to challenges associated with blood-gorging. As will be demonstrated, the overall control of events associated with gorging is complex, and utilizes a range of neuropeptide families and serotonin acting upon a variety of tissues to bias them towards a new functional state.