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Acute ethanol treatment increases amiloride‐sensitive epithelial sodium channel (ENaC) activity in A6 distal nephron kidney cells
Author(s) -
Bao HuiFang,
Helms My N.,
Ma HePing,
Eaton Douglas C.
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a796-a
Subject(s) - epithelial sodium channel , chemistry , amiloride , ethanol , nephron , endocrinology , medicine , patch clamp , sodium , homeostasis , alcohol , kidney , apical membrane , biophysics , receptor , biochemistry , biology , membrane , organic chemistry
Changes in electrolyte and fluid homeostasis are commonly observed in patients with a history of chronic alcohol abuse. Recently, we have shown that chronic ethanol consumption alters Na + channel activity; however, the molecular mechanisms responsible for changes in Na + transport are not clearly understood. Therefore in the present study, we examined the effect of acute ethanol treatment on A6 distal nephron kidney cells. Results from cell‐attached patch clamp studies show that apical application of 2% (or 343mM) ethanol to A6 cells grown on permeable supports significantly increased ENaC open probability (P o ) from 0.09 ± 0.04 to 0.22 ± 0.16 [n=8, P<0.05] as well as the number of active channels (N) on the apical surface. The number of channels increased from 2 ± 1 to 4 ± 2 after 2% ethanol treatment, P<0.05. Interestingly, 2% methanol, an alcohol with structural similarity to ethanol, failed to increase ENaC activity in A6 cells in 4 independent studies (average P o values were 0.20 ± 0.17 before and 0.08 ± 0.06 after methanol treatment, without significant changes in N). To account for possible changes in osmolality, we applied an equal volume of water to cell attached patch clamp recordings. In these control studies, water did not increase ENaC activity; P o values were 0.12 ± 0.06 before and 0.09 ± 0.04 after decreasing osmolality with water (n=6) and the number of active channels remained unchanged. In summary, our results show that acute 2% ethanol treatment significantly increases ENaC NP o values in A6 distal nephron cells and suggest that chronic ethanol ingestion may directly alter ion channel function.