Premium
Differential regulation of epithelial sodium channel subunits in the brain by sodium rich aCSF
Author(s) -
Amin Md Shahrier,
Wang HongWei,
Leenen Frans H H
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
Subject(s) - sodium channel , epithelial sodium channel , sodium , chemistry , differential (mechanical device) , microbiology and biotechnology , channel (broadcasting) , biophysics , biology , computer science , physics , telecommunications , organic chemistry , thermodynamics
All three subunits of the epithelial sodium channel (ENaC) are expressed in the brain. Blockade of ENaC in the brain by benzamil prevents sympathetic hyperactivity and hypertension in salt sensitive rats and following intracerebroventricular (icv) infusion of Na rich aCSF or aldosterone. The aim of this study was to assess the effect of Na rich aCSF on ENaC and whether spironolactone prevents these effects. ENaC expression was assessed by quantitative RT‐PCR and immunohistochemistry in the brains of Wistar rats following 2 weeks icv infusion (@5 μl/hr) of aCSF (145 mmol/L Na), aCSF & spironolactone (@ 100 ng/hr), Na rich aCSF (800 mmol/L Na) or, Na rich aCSF & spironolactone. Increasing CSF [Na + ] by 5–6 mmol/L with Na rich aCSF, increased α and β ENaC immunoreactivity in the ependyma of the anteroventral 3 rd ventricle (AV3V) by 20–30% which was prevented by spironolactone; increased γ ENaC mRNA in the supraoptic nucleus (SON) 2 fold, also prevented by spironolactone; but decreased α ENaC mRNA in the paraventricular nucleus (PVN) by 25% which was not prevented by spironolactone. Na rich aCSF did not affect immunoreactivity to the ENaC subunits in the SON & PVN. The results suggest non‐coordinate regulation of ENaC subunits by Na rich aCSF in different areas. Increased [Na + ] in the AV3V region caused by enhanced ENaC expression in the ependyma may contribute to sympathoexcitation and hypertension.