Immunolocalization of hyperpolarization-activated cationic HCN1 and HCN3 channels in the rat nephron: regulation of HCN3 by potassium diets
Por:
Lopez-Gonzalez, Zinaeli, Ayala-Aguilera, Cosete, Martinez-Morales, Flavio, Galicia-Cruz, Othir, Salvador-Hernandez, Carolina, Pedraza-Chaverri, Jose, Medeiros, Mara, Maria Hernandez, Ana, Escobar, Laura I.
Publicada:
1 ene 2016
Resumen:
Hyperpolarization-activated cationic and cyclic nucleotide-gated
channels (HCN) comprise four homologous subunits (HCN1-HCN4). HCN
channels are found in excitable and non-excitable tissues in mammals. We
have previously shown that HCN2 may transport ammonium (NH4+), besides
sodium (Na+), in the rat distal nephron. In the present work, we
identified HCN1 and HCN3 in the proximal tubule (PT) and HCN3 in the
thick ascending limb of Henle (TALH) of the rat kidney. Immunoblot
assays detected HCN1 (130 kDa) and HCN3 (90 KDa) and their truncated
proteins C-terminal HCN1 (93 KDa) and N-terminal HCN3 (65 KDa) in
enriched plasma membranes from cortex (CX) and outer medulla (OM), as
well as in brush-border membrane vesicles Immunofluorescence assays
confirmed apical localization of HCN1 and HCN3 in the PT. HCN3 was also
found at the basolateral membrane of TALH. We evaluated chronic changes
in mineral dietary on HCN3 protein abundance Animals were fed with three
different diets: sodium-deficient (SD) diet, potassium-deficient (KD)
diet, and high-potassium (HK) diet. Up-regulation of HCN3 was observed
in OM by KD and in CX and OM by HK; the opposite effect occurred with
the N-terminal truncated HCN3 in CX (KD) and OM (HK). SD diet did not
produce any change. Since HCN channels activate with membrane
hyperpolarization, our results suggest that HCN channels may play a role
in the Na+-K+-ATPase activity, contributing to Na+, K+, and acid base
homeostasis in the rat kidney.
Filiaciones:
Univ Nacl Autonoma Mexico, Fac Med, Dept Fisiol, Mexico City 04510, DF, Mexico
Univ Autonoma San Luis Potosi, Fac Med, Dept Farmacol, San Luis Potosi, Mexico
Univ Nacl Autonoma Mexico, Fac Quim, Dept Biol, Mexico City 04510, DF, Mexico
Hosp Infantil Mexico Dr Federico Gomez, Lab Invest Nefrol & Metab, Mexico City, DF, Mexico
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