Effects of amiloride on isolated Malpighian tubules of the yellow fever mosquito (Aedes aegypti)

Hegarty, J. L.; Zhang, B.; Carroll, M. C.; Cragoe, Edward J.; Beyenbach, Klaus W.

doi:10.1016/0022-1910(92)90057-k

Cited by 30 publications

(9 citation statements)

References 14 publications

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“…Present hypotheses consider the exchanger to be related to the cation proton antiporter (CPA) superfamily, which includes the CPA1 or solute carrier 9 (SLC9) family of Na/H exchangers (NHEs) and the CPA2 family of Na/H antiporters (NHAs). Supporting these hypotheses are the observations that amiloride and amiloride-based compounds inhibit 1) fluid secretion in isolated Malpighian tubules of dipterans (27,32,56) and 2) electrogenic K ϩ /H ϩ antiport in vesicles derived from highly purified apical membranes of K ϩ -secreting cells of the Manduca midgut epithelium (83). A recent study on Aedes Malpighian tubules by Kang'ethe and colleagues (34) has proposed that the apical cation/H ϩ exchanger is an ortholog of mammalian NHE8 (SLC9A8), whereas a more recent study on Drosophila Malpighian tubules by Day and colleagues (21) has proposed that the exchanger is an ortholog of bacterial NHAs [i.e., the bacterial K ϩ efflux (Kef) family].…”

mentioning

confidence: 81%

NHE8 is an intracellular cation/H⁺exchanger in renal tubules of the yellow fever mosquitoAedes aegypti

Piermarini

Weihrauch²,

Meyer³

et al. 2009

American Journal of Physiology-Renal Physiology

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The goal of this study was to identify and characterize the hypothesized apical cation/H(+) exchanger responsible for K(+) and/or Na(+) secretion in the renal (Malpighian) tubules of the yellow fever mosquito Aedes aegypti. From Aedes Malpighian tubules, we cloned "AeNHE8," a full-length cDNA encoding an ortholog of mammalian Na(+)/H(+) exchanger 8 (NHE8). The expression of AeNHE8 transcripts is ubiquitous among mosquito tissues and is not enriched in Malpighian tubules. Western blots of Malpighian tubules suggest that AeNHE8 is expressed primarily as an intracellular protein, which was confirmed by immunohistochemical localizations in Malpighian tubules. AeNHE8 immunoreactivity is expressed in principal cells of the secretory, distal segments, where it localizes to a subapical compartment (e.g., vesicles or endosomes), but not in the apical brush border. Furthermore, feeding mosquitoes a blood meal or treating isolated tubules with dibutyryl-cAMP, both of which stimulate a natriuresis by Malpighian tubules, do not influence the intracellular localization of AeNHE8 in principal cells. When expressed heterologously in Xenopus laevis oocytes, AeNHE8 mediates EIPA-sensitive Na/H exchange, in which Li(+) partially and K(+) poorly replace Na(+). The expression of AeNHE8 in Xenopus oocytes is associated with the development of a conductive pathway that closely resembles the known endogenous nonselective cation conductances of Xenopus oocytes. In conclusion, AeNHE8 does not mediate cation/H(+) exchange in the apical membrane of Aedes Malpighian tubules; it is more likely involved with an intracellular function.

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mentioning

confidence: 81%

NHE8 is an intracellular cation/H⁺exchanger in renal tubules of the yellow fever mosquitoAedes aegypti

Piermarini

Weihrauch²,

Meyer³

et al. 2009

American Journal of Physiology-Renal Physiology

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“…In Malpighian tubules of Aedes aegypti, 1·mmol·l -1 amiloride inhibits transepithelial fluid secretion by 60% without significant effects on electroconductive transport pathways (Hegarty et al, 1992). The inhibition of Na/H exchange across the basolateral membrane inhibits not only transepithelial NaCl secretion but also KCl secretion, suggesting again the coupling of electroconductive and electroneutral transport.…”

Section: Inhibition Of Electroneutral Transport Systemsmentioning

confidence: 93%

The mechanism of action of the antidiuretic peptide Tenmo ADFa in Malpighian tubules ofAedes aegypti

Massaro

Lee

Patel

et al. 2004

Journal of Experimental Biology

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“…The cAMP-activated Na + conductance and fluid secretion rates are both blocked by peritubular amiloride, which suggests the involvement of degenerins/ epithelial Na + -channels, e.g. ENaC (Hegarty et al 1992, Beyenbach & Masia 2002. However, at least in the Malpighian tubules of Drosophila, the closest orthologs of ENaC (i.e.…”

Section: The Pump and Energy Sourcementioning

confidence: 99%

Transcellular and paracellular pathways of transepithelial fluid secretion in Malpighian (renal) tubules of the yellow fever mosquito Aedes aegypti

2010

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Isolated Malpighian tubules of the yellow fever mosquito secrete NaCl and KCl from the peritubular bath to the tubule lumen via active transport of Na + and K + by principal cells. Lumenpositive transepithelial voltages are the result. The counter-ion Cl − follows passively by electrodiffusion through the paracellular pathway. Water follows by osmosis, but specific routes for water across the epithelium are unknown. Remarkably, the transepithelial secretion of NaCl, KCl and water is driven by a H + V-ATPase located in the apical brush border membrane of principal cells and not the canonical Na/K ATPase. A hypothetical cation/H + exchanger moves Na + and K + from the cytoplasm to the tubule lumen. Also remarkable is the dynamic regulation of the paracellular permeability with switch-like speed which mediates in part the post-blood-meal diuresis in mosquitoes. For example, the blood meal the female mosquito takes to nourish her eggs triggers the release of kinin diuretic peptides that 1) increases the Cl − conductance of the paracellular pathway, and 2) assembles V 1 and V 0 complexes to activate the H + V-ATPase and cation/H + exchange close by. Thus, transcellular and paracellular pathways are both stimulated to quickly rid the mosquito of the unwanted salts and water of the blood meal. Stellate cells of the tubule appear to serve a metabolic support role, exporting the HCO 3 − generated during stimulated transport activity. Septate junctions define the properties of the paracellular pathway in Malpighian tubules, but the proteins responsible for the permselectivity and barrier functions of the septate junction are unknown.

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Effects of amiloride on isolated Malpighian tubules of the yellow fever mosquito (Aedes aegypti)

Cited by 30 publications

References 14 publications

NHE8 is an intracellular cation/H⁺exchanger in renal tubules of the yellow fever mosquitoAedes aegypti

NHE8 is an intracellular cation/H⁺exchanger in renal tubules of the yellow fever mosquitoAedes aegypti

The mechanism of action of the antidiuretic peptide Tenmo ADFa in Malpighian tubules ofAedes aegypti

Transcellular and paracellular pathways of transepithelial fluid secretion in Malpighian (renal) tubules of the yellow fever mosquito Aedes aegypti

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Effects of amiloride on isolated Malpighian tubules of the yellow fever mosquito (Aedes aegypti)

Cited by 30 publications

References 14 publications

NHE8 is an intracellular cation/H+exchanger in renal tubules of the yellow fever mosquitoAedes aegypti

NHE8 is an intracellular cation/H+exchanger in renal tubules of the yellow fever mosquitoAedes aegypti

The mechanism of action of the antidiuretic peptide Tenmo ADFa in Malpighian tubules ofAedes aegypti

Transcellular and paracellular pathways of transepithelial fluid secretion in Malpighian (renal) tubules of the yellow fever mosquito Aedes aegypti

Contact Info

Product

Resources

About

NHE8 is an intracellular cation/H⁺exchanger in renal tubules of the yellow fever mosquitoAedes aegypti

NHE8 is an intracellular cation/H⁺exchanger in renal tubules of the yellow fever mosquitoAedes aegypti