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Voltage‐gated chloride channels in storage cells of the anhydrobiotic eutardigrade Richtersius coronifer
Author(s) -
Willumsen Niels J,
Jensen Christel Barker,
Ramløv Hans
Publication year - 2010
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.24.1_supplement.813.5
Subject(s) - gating , membrane potential , pipette , patch clamp , ion channel , chemistry , reversal potential , conductance , biophysics , ion , analytical chemistry (journal) , biology , chromatography , receptor , biochemistry , physics , organic chemistry , condensed matter physics
Tardigrades comprise polyextremophilic species that can survive in an anhydrobiotic state for years. Anhydrobiosis may be dependent on properties of the free floating storage cells found in the body cavity of all tardigrades. We studied ion channels in the storage cell membrane with patch clamp technique, using native cells from the eutardigrade Richtersius coronifer . In cell‐attached configuration the most frequently encountered ion channel had a linear i/V‐relationship with a reversal potential (V rev ) of ~0.4 mV (n ≥6). The single‐channel conductance was 82.4±0.0 pS (mean±SE, n≥6). Binomial analysis of patches with 2–4 active channels showed stochastic behavior. The open‐state probability increased with the pipette potential, indicating voltage‐gating. In whole‐cell configuration the currents showed outward rectification with V rev = −18.2±1.1 mV (mean±SE, n=24), closest to the equilibrium potential for Cl − . Perfusion with Na‐gluconate Ringer right‐shifted V rev from −19.5±1.9 to 4.6±1.3 mV, and the current decreased significantly (mean±SE, n=5), confirming that a significant component of the whole‐cell current is attributed to Cl − channels. This was verified by perfusion with KCl Ringer (n=5) and addition of BaCl 2 (n=7), neither of which significantly changed V rev . Future studies are needed to firmly establish the identity and function of the demonstrated ion channel in storage cells.