The effect of putative diuretic factors on in vivo urine production in the mosquito, Aedes aegypti

Changes in total urine production were measured in the mosquito, Aedes aegypti, following injection of 5-hydroxytryptamine (5-HT), Culex salinarius diuresin, culekinin depolarizing peptides (CDP-I, II and III) or the At aegypti leucokinin peptides (ALP=I, II and III). All stimulated total urine production in a dose dependent manner. 5-HT was the least potent in urine production experiments with ED50 values nearly 100-fold higher than other diuretic agonists. Doses greater than 2 x 10(-4) mu moles inhibited urine production, suggesting either the occurrence of receptor down regulation, more than one type of 5-HT receptor, or increases in hindgut resorption of urine. The ALPs had relatively low ED50 values compared to the CDPs Suggesting that the endogenous peptides may have higher receptor binding affinities, Injection of mosquitoes with polyclonal antisera raised against either ALP-I or C. salinarius diuresin significantly reduced the response to injections of the respective peptides. The evidence presented above suggests that mosquito leucokinins and the C. salinarius diuresin function in the neuroendocrine regulation of urine production in the mosquito. (C) 1999 Elsevier Science Ltd. All rights reserved.