Referenced in: none

Automatically associated channels: HCN1 , HCN2

Title: Angiotensin II induces protein overexpression of hyperpolarization-activated cyclic nucleotide-gated channels in primary cultured nodose neurons.

Authors: Jinxu Liu, Libin Zhang, Huiyin Tu, Yu-Long Li

Journal, date & volume: , 2012 Mar 24 , ,

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/22465246

Abstract
Modulating ion channel function includes acutely affecting the kinetics of the ion channels and chronically changing the expression of ion channels. Our previous study showed that angiotensin II (Ang II) acutely increased hyperpolarization-activated cyclic nucleotide-gated (HCN) currents in nodose ganglion (NG) neurons via NADPH oxidase-superoxide signaling. Therefore, the present study was to measure chronic treatment with Ang II on protein expression of the HCN channels in the primary cultured rat NG neurons. Immunofluorescent staining data showed that HCN1 was expressed in the A-type NG neurons, and HCN2 was expressed in the C-type NG neurons. Chronic treatment of Ang II (100 nM, 12 h) induced the protein expression of HCN2 besides the overexpression of HCN1 in the A-type NG neurons; and the overexpression of HCN2 in the C-type NG neurons. An Ang II type I receptor antagonist (1 μM losartan), a NADPH oxidase inhibitor (100 μM apocynin), or a superoxide dismutase mimetic (1mM tempol) attenuated the effect of Ang II to increase the protein expression of the HCN channels in rat nodose neurons. Whole cell patch-clamp data further confirmed that chronic treatment of Ang II (100 nM, 12 h) significantly enhanced the density of HCN currents in A- and C-type NG neurons. Above three inhibitors significantly inhibited the Ang II-induced increase of the HCN channel density in rat NG neurons. These findings suggest that Ang II-NADPH oxidase-superoxide signaling chronically regulates the protein expression of the HCN channels in rat nodose neurons.