title: The excretion of NaCl and KCl loads in mosquitoes. 1. Control data.
abstract: The handling of Na(+) and K(+) loads was investigated in isolated Malpighian tubules and in whole mosquitoes of Aedes aegypti. Isolated Malpighian tubules bathed in Na(+)-rich Ringer solution secreted Na(+)-rich fluid, and tubules bathed in K(+)-rich Ringer solution secreted K(+)-rich fluid. Upon Na(+) loading the hemolymph, the mosquito removed 77% the injected Na(+) within the next 30 min. The rapid onset and magnitude of this diuresis and the excretion of more Na(+) than can be accounted for by tubular secretion in vitro is consistent with the release of the calcitonin-like diuretic hormone in the mosquito to remove the Na(+) load from the hemolymph. Downstream, K(+) was reabsorbed with water in the hindgut, which concentrated Na(+) in excreted urine hyperosmotic to the hemolymph. Upon K(+) loading the hemolymph, the mosquito took 2 h to remove 100% of the injected K(+) from the hemolymph. The excretion of K(+)-rich isosmotic urine was limited to clearing the injected K(+) from the hemolymph with a minimum of Cl(-) and water. As a result, 43.3% of the injected Cl(-) and 48.1% of the injected water were conserved. The cation retained in the hemolymph with Cl(-) was probably N-methyl-d-glucamine, which replaced Na(+) in the hemolymph injection of the K(+) load. Since the tubular secretion of K(+) accounts for the removal of the K(+) load from the hemolymph, the reabsorption of K(+), Na(+), Cl(-), and water must be inhibited in the hindgut. The agents mediating this inhibition are unknown.
authors: Department of Biomedical Sciences, Cornell University, Ithaca, New York;
authors: Rebecca M
authors: RM
authors: Hine
authors: Department of Entomology, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, Ohio; and.
authors: Matthew F
authors: MF
authors: Rouhier
authors: Department of Biomedical Sciences, Cornell University, Ithaca, New York;
authors: Seokhwan Terry
authors: ST
authors: Park
authors: Institute of Pesticide Science, Northwestern Agricultural and Forestry University, Yangling, Shaanxi, China.
authors: Zhijun
authors: Z
authors: Qi
authors: Department of Entomology, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, Ohio; and.
authors: Peter M
authors: PM
authors: Piermarini
authors: Department of Biomedical Sciences, Cornell University, Ithaca, New York; kwb1@cornell.edu.
authors: Klaus W
authors: KW
authors: Beyenbach
mesh_terms: D000818:Animals; D001826:Body Fluids / Q000502:physiology; D009033:Culicidae; D004231:Diuresis / Q000502:physiology; D017136:Ion Transport / Q000502:physiology; D008317:Malpighian Tubules / Q000378:metabolism*; D011189:Potassium Chloride / Q000378:metabolism* / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism*; D012965:Sodium Chloride / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D012965:Sodium Chloride; D011189:Potassium Chloride; D012964:Sodium
keywords: Aedes aegypti; Malpighian tubules; NaCl and KCl loads; excretion in mosquitoes; renal transport mechanisms