Abstract
Abstract 199: Hydrogen Peroxide Mediates the pH Conditioned Chloride Conductance in Nodose Ganglia Neurons
Hypertension (Dallas, Tex. 1979), Vol.60(suppl_1)
09/2012
DOI: 10.1161/hyp.60.suppl_1.A199
Abstract
pH sensitivity has been rarely studied in vagal afferents of nodose ganglia (NG) neurons. Using whole-cell patch-clamp technique in isolated NG neurons, we recently identified a pH-conditioned Cl
-
current (pH-I) that was evoked following 2 or 3 brief (10s) exposures to low extracellular pH (7.0-6.0) in 16 of 22 (70%) cells (FASEB J, 2012). The current is large (904.3±159.9pA) and prolonged, lasting 10∼15 minutes, and causes significant depolarization (Δ35.2±4.4mV). In the present study, we tested the hypothesis that reactive oxygen species (ROS) mediates this pH-conditioned Cl
-
conductance. We found that the rate of increase in fluorescence [(F-F
0
)/F
0
] of NG neurons loaded with dihydroethidine (ROS dye) rose dramatically following the brief exposures to pH 6.0 from a control of 0.04±0.01 to 0.12±0.02 units/min over 10∼15 minutes (n=31 neurons, p<0.01). Moreover superfusion of neurons with H
2
O
2
induced currents that mimicked the pH conditioned currents. Because of similarities between the pH-conditioned Cl
-
conductance and the previously described “swell-activated” Cl
-
current induced with hypoosmotic solutions, we superfused the NG neurons with the H
2
O
2
scavenger PEG-catalase (1000 units/ml). PEG-catalase blocked significantly (p<0.01) the “swell” response to 210 mOsm from 23.3±6.3pA/pF to 0.57±0.39 pA/pF (n=4) as well as the pH-conditioned response from 25.7±6.5pA/pF (n=6) to 6.9±1.4 pA/pF (n=12). The superoxide scavenger PEG-SOD did not affect the current. These results indicate that both pH-conditioned and swell-induced responses are mediated by H
2
O
2
. Opening of these outward Cl
-
conductances that cause sustained depolarization of vagal afferents may induce a beneficial reflex sympathoinhibition during myocardial ischemia/acidosis or initiate a gastro-intestinal post-prandial satiety reflex.
Details
- Title: Subtitle
- Abstract 199: Hydrogen Peroxide Mediates the pH Conditioned Chloride Conductance in Nodose Ganglia Neurons
- Creators
- Runping Wang - University of IowaYongjun Lu - University of IowaCarol A Whiteis - University of IowaChristopher J Benson - University of IowaMark W Chapleau - University of IowaFrançs M Abboud - University of Iowa
- Resource Type
- Abstract
- Publication Details
- Hypertension (Dallas, Tex. 1979), Vol.60(suppl_1)
- DOI
- 10.1161/hyp.60.suppl_1.A199
- ISSN
- 0194-911X
- eISSN
- 1524-4563
- Language
- English
- Date published
- 09/2012
- Academic Unit
- Cardiovascular Medicine; Stead Family Department of Pediatrics; Nephrology; Molecular Physiology and Biophysics; Neuroscience and Pharmacology; Fraternal Order of Eagles Diabetes Research Center; Internal Medicine; Critical Care
- Record Identifier
- 9984303006002771
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