'In situ' high pressure confocal Ca2+-fluorescence microscopy in skeletal muscle: A new method to study pressure limits in mammalian cells

Friedrich O, von Wegner F, Hartmann M, Frey B, Sommer K, Ludwig H, Fink R (2006)

Publication Language: English

Publication Status: Published

Publication Type: Journal article, Original article

Publication year: 2006

Journal

Undersea & Hyperbaric Medicine Undersea and Hyperbaric Medical Society, Inc.

Publisher: Undersea and Hyperbaric Medical Society, Inc.

Book Volume: 33

Pages Range: 181-95

Journal Issue: 3

URI: https://www.scopus.com/record/display.uri?eid=2-s2.0-33746618017∨igin=inward

Abstract

We combined 'in situ' high pressure microscopy with confocal laser scanning microscopy to directly study Ca2+ homeostasis in intact mammalian (murine) skeletal muscle fibres during high pressure exposure up to 35 MPa. Cytosolic Fluo-4 and mitochondrial Rhod-2 Ca2+ fluorescence were simultaneously monitored. To separate changes in Ca2+ and direct/indirect effects of pressure on the dye, experiments in permeabilized ('skinned') muscle fibres were performed at a fixed Ca2+ concentration. Normalized Fluo-4 fluorescence sharply declined up to 10 MPa but showed a plateau between 10 MPa and -35 MPa. In the intact fibre, Fluo-4 fluorescence exponentially decreased during pressurization to 35 MPa with a pressure constant of pi-5 MPa whereas mitochondrial Rhod-2 fluorescence exponentially increased with a four-fold larger pi. Holding the pressure at 35 MPa almost did not change Fluo-4 fluorescence. However, Rhod-2 fluorescence started to decrease after -40 min. Upon decompression, Rhod-2 and Fluo-4 fluorescence increased exponentially with similar pi. However, initial Fluo-4 fluorescence values were not restored. Our results are in agreement with pressure induced Ca2+ leakage from the sarcoplasmic reticulum. Ca2+ might then be taken up in large amounts by mitochondria preventing cytosolic increase in Ca2+. Prolonged pressure applications (-40 min at 35 MPa) seem to destabilize mitochondrial function with release of Ca2+ from mitochondria back into the cytosol and eventually mechanical activation resulting in irreversible contractures. The pressure induced disturbance of Ca2+ homeostasis might have important implications for the pressure exposure limits and/or dive profiles of deep sea mammals.

Authors with CRIS profile

Oliver Friedrich Lehrstuhl für Medizinische Biotechnologie Benjamin Frey Department of Radiation Oncology

Involved external institutions

Ruprecht-Karls-Universität Heidelberg DE Germany (DE) Technische Universität München (TUM) DE Germany (DE) Goethe-Universität Frankfurt am Main DE Germany (DE)

How to cite

APA:

Friedrich, O., von Wegner, F., Hartmann, M., Frey, B., Sommer, K., Ludwig, H., & Fink, R. (2006). 'In situ' high pressure confocal Ca2+-fluorescence microscopy in skeletal muscle: A new method to study pressure limits in mammalian cells. Undersea & Hyperbaric Medicine, 33(3), 181-95.

MLA:

Friedrich, Oliver, et al. "'In situ' high pressure confocal Ca2+-fluorescence microscopy in skeletal muscle: A new method to study pressure limits in mammalian cells." Undersea & Hyperbaric Medicine 33.3 (2006): 181-95.

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