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Aldosterone acutely increases the production of reactive oxygen species (ROS) and intracellular calcium concentration [Ca 2+ ] i in neurons of the paraventricular nucleus (PVN): An in vitro study
Author(s) -
BadauePassos Daniel,
Xue Baojian,
Johnson Ralph Fred,
Beltz Terry G,
Johnson Alan Kim,
Hay Meredith
Publication year - 2008
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.22.1_supplement.737.39
Subject(s) - reactive oxygen species , chemistry , biophysics , nucleus , calcium , aldosterone , fluorescence microscope , calcium in biology , in vitro , fluorescence , intracellular , biochemistry , microbiology and biotechnology , endocrinology , biology , organic chemistry , physics , quantum mechanics
Besides the well known genomic or transcriptional effects of aldosterone (ALDO), non‐transcription‐like (rapidly acting) actions have been recently demonstrated. We investigated the effects of ALDO on changes in [Ca 2+ ] i and ROS production in PVN cells in vitro. Neurons in the PVN were visualized by confocal microscopy. Changes in [Ca 2+ ] i were measured as changes in the fluorescence of Fluo‐4 AM, a [Ca 2+ ] i marker dye. To estimate ROS, we measured the changes in the ethidium fluorescence which is directly proportional to the oxidation of dihydroethidium (DHE) by ROS. Male rats were decapitated and the brains were promptly removed, cooled in an artificial cerebrospinal fluid (aCSF) containing 7.5% sucrose and cut on a vibratome. The cells were loaded with Fluo‐4 (18 μM) or DHE (20 μM) added to oxygenated aCSF (34±0.5°C) for 1h. The slices were then placed in a chamber for microscopic visualization of fluorescence. The chamber was perfused with heated and oxygenated aCSF and ALDO (1 μM) or KCl (60 mM). Three‐dimensional images were obtained every minute for 1h. The perfusion of ALDO increased both [Ca 2+ ] i (Δ=69.9±10.6%) and ROS (Δ=26.0±2.5%) within 15–30 min in the PVN neurons (i.e., KCl responsive cells). The increase in [Ca 2+ ] i suggests that ALDO can acutely activate neurons in the PVN, and the enhanced ROS production implies that ROS may mediate a non‐transcriptional effect of ALDO. (Support: NIH HL‐59676 & HL‐62261)