Document Detail

Sodium-proton exchange in crayfish.
MedLine Citation:
PMID:  12421538     Owner:  NLM     Status:  MEDLINE    
Recently, three proton pump inhibitors were shown to have no effect on proton excretion and little on Na uptake in tapwater-adapted (TW) crayfish, while all three reduced Na-H exchange in salt-depleted (SD) animals. It appeared that the exchange was mediated by the Na channel-H pump in SD crayfish but not in TW animals. An alternative, a 2Na-1H exchanger, might function in the latter. To test this, the effects of amiloride (AM) and ethylisopropyl AM (EIPA) on Na fluxes were observed. AM inhibits the Na channel but is a much weaker blocker of Na-H exchangers. In contrast, EIPA inhibits exchangers but acts weakly on the Na channel. If an exchanger functions in TW crayfish, we should expect EIPA to block Na influx in them with AM having a weaker action. The reverse should be true in SD animals. Experimental data showed that EIPA was a potent inhibitor of Na influx in TW crayfish with half-maximal inhibition at about 0.2 microM. However, AM proved to be equipotent. In SD crayfish, EIPA was as effective as in TW animals, and again AM was equally potent. The data fail to show the expected differential action. Therefore, AM and its analogues cannot be used to distinguish between the two models of Na-H exchange in crayfish.
Leonard B Kirschner
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Publication Detail:
Type:  Journal Article; Review    
Journal Detail:
Title:  Biochimica et biophysica acta     Volume:  1566     ISSN:  0006-3002     ISO Abbreviation:  Biochim. Biophys. Acta     Publication Date:  2002 Nov 
Date Detail:
Created Date:  2002-11-07     Completed Date:  2003-01-15     Revised Date:  2009-11-03    
Medline Journal Info:
Nlm Unique ID:  0217513     Medline TA:  Biochim Biophys Acta     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  67-71     Citation Subset:  IM    
School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USA.
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MeSH Terms
Adaptation, Physiological
Amiloride / analogs & derivatives*,  pharmacology
Astacoidea / drug effects,  metabolism*
Models, Animal
Sodium / metabolism*
Sodium Channels / drug effects,  metabolism
Sodium-Hydrogen Antiporter / analysis,  antagonists & inhibitors,  metabolism*
Vacuolar Proton-Translocating ATPases / antagonists & inhibitors
Reg. No./Substance:
0/Sodium Channels; 0/Sodium-Hydrogen Antiporter; 1154-25-2/ethylisopropylamiloride; 2609-46-3/Amiloride; 7440-23-5/Sodium; EC 3.6.1.-/Vacuolar Proton-Translocating ATPases

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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