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Osmotic stimulation of renin release from single mouse juxtaglomerular cells
Author(s) -
Skott Ole,
Jensen Boye L.,
Madsen Kirsten,
Jorgensen Finn,
Hansen Pernille B.,
Friis Ulla G.
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.736.8
Subject(s) - tonicity , renin–angiotensin system , intracellular , stimulation , chemistry , endocrinology , medicine , patch clamp , biophysics , pipette , biology , receptor , biochemistry , blood pressure
We tested whether cell swelling stimulates renin release from juxtaglomerular cells (JG) via activation of the prostaglandin system. Lowering osmolality by 10 mOsm/kg led to a 20‐fold increase in renin release from superfused JG cells. The whole cell patch clamp approach was used to measure cell membrane capacitance (Cm) as an index of exocytosis. Exposure of single JG‐cells to 3.6% and 5.5% hypotonic solution led to increases in Cm of 7±1.8% (n=5) and 8.3±1.4% (n=8) that were blocked by indomethacin (n=4) and which were absent in JG‐cells from COX‐2−/− mice. In COX‐2+/+ littermates, a 5.5% hypotonic solution led to a significant increase in capacitance (8.5±2.2%, n=4). JG cells from COX 2−/− mice responded to external PGE2 with a significant increase in capacitance. Hypotonic treatment (5, 10 and 20% reduction in osmolality) enhanced the production of cAMP in isolated JG cells. Intracellular dialysis of the protein kinase A inhibitor RpcAMPs (25 μM) in the patch pipette blocked the ability of hypotonic treatment to increase cell membrane capacitance. Consistent with cAMP‐induced activation of BKCa channels by hypotonic treatment, an enhanced outward current was observed at positive potentials. We suggest that cell swelling stimulates renin release from single juxtaglomerular cells by activation of COX‐2, release of PGE2, and activation of cAMP‐coupled EP‐receptors.