Distribution, activity and evidence for the release of an anti-diuretic peptide in the kissing bug Rhodnius prolixus.
In the haematophagous insect Rhodnius prolixus, diuresis is accomplished through the combined actions of peptidergic diuretic hormones and 5-HT released from neurohaemal sites on the abdominal nerves. Preliminary work on anti-diuresis in this blood-feeder, previously believed to occur through a decrease in the levels of the diuretic factors, indicates that an anti-diuretic hormone, with properties similar to CAP2b (pELYAFPRVamide; recently renamed Mas-CAPA-1), might also be present in R. prolixus. Here, we present evidence from immunohistochemical analysis that suggests a PRXamide-like neuropeptide may be released from the abdominal neurohaemal sites beginning 3-4 h following feeding; a time that coincides with the cessation of diuresis. We also show evidence for an endogenous factor, isolated from the central nervous system using reversed-phase high performance liquid chromatography, which mimics the effects of Mas-CAPA-1. Specifically, this endogenous anti-diuretic factor inhibits rates of 5-HT-stimulated secretion in a dose-dependent manner and elevates intracellular cGMP levels of Malpighian tubules stimulated with 5-HT.
Paluzzi
Jean-Paul
JP
Department of Biology, University of Toronto at Mississauga, Mississauga, ON, L5L 1C6, Canada. jeanpaul.paluzzi@utoronto.ca
Orchard
Ian
I
D000818:Animals; D050034:Antidiuretic Agents / Q000378:metabolism*; D002490:Central Nervous System / Q000033:anatomy & histology / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D005247:Feeding Behavior; D005724:Ganglia / Q000033:anatomy & histology / Q000378:metabolism; D007150:Immunohistochemistry; D007814:Larva / Q000033:anatomy & histology / Q000378:metabolism; D008317:Malpighian Tubules / Q000378:metabolism; D009479:Neuropeptides / Q000378:metabolism*; D012239:Rhodnius / Q000033:anatomy & histology / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism; D013997:Time Factors
D050034:Antidiuretic Agents; D009479:Neuropeptides; D012701:Serotonin; D006152:Cyclic GMP