An amiloride-sensitive H+-gated Na+ channel in Caenorhabditis elegans body wall muscle cells

Autor: Jospin, M., Allard, Béatrice
Přispěvatelé: Physiologie intégrative, cellulaire et moléculaire (PICM), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon
Jazyk: angličtina
Rok vydání: 2004
Předmět:
Zdroj: The Journal of Physiology
The Journal of Physiology, Wiley, 2004, 559, pp.715-720. ⟨10.1113/jphysiol.2004.069971⟩
ISSN: 0022-3751
1469-7793
Popis: About 30 genes are predicted to encode degenerin/epithelial sodium channels (DEG/ENaCs) in Caenorhabditis elegans but the gating mode of these channels has not been determined. Using the whole-cell configuration of the patch-clamp technique in acutely dissected C. elegans, we investigated the effects of H+ as a potential activating factor of DEG/ENaCs on electrical properties of body wall muscle cells. Under current-clamp conditions, decreasing external pH from 7.2 to 6.1 led to a reversible depolarization of muscle cells associated with a decrease in input resistance which was partially inhibited by amiloride. Under voltage-clamp conditions, extracellular acidification activated an inward desensitizing current at -60 mV. In the absence of external Ca2+, H+ -gated channels were found to be slightly more permeable to Na+ than to K+ and were blocked by amiloride with a K0.5 of 31 microm at -60 mV. An inward current could be also activated by protons in a GABA receptor null mutant in the presence of D-tubocurare and in an unc-105 null mutant. These results demonstrate that ion channels sharing common properties with mammalian acid-sensing ion channels (ASICs) are functional in C. elegans muscle which should prove useful for understanding proton sensing in animals.
Databáze: OpenAIRE
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