Quantitative assessment of [Ca2+](i) levels in rat skeletal muscle in vivo

András Tóth, Tamás Ivanics, Zoltán Ruttner, Dick W. Slaaf, Robert S. Reneman, László Ligeti

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6 Citations (Scopus)


Intracellular free Ca2+ concentration ([Ca2+](i)) plays an essential role in physiological regulatory processes and common pathological conditions. Better understanding of these phenomena is still hampered by problems encountered in the quantitative assessment of [Ca2+](i) changes, especially in blood-perfused organs. This study demonstrates that the ratiometric fluorescence technique can be adapted for quantitative in vivo [Ca2+](i) determinations. The rat spinotrapezius muscle was topically loaded with indo 1-AM and imaged by a cooled digital camera. Ratio images were calculated in small regions (100 μm x 100 μm) practically devoid of large vessels in the resting state, after 30 min of ischemia, 20 min of reperfusion, or ionomycin or manganate treatments. When we assumed an average [Ca2+](i) of 100 nM in the resting blood-perfused muscle, ischemia increased [Ca2+](i) to ~200 nM. During reperfusion [Ca2+](i) decreased to ~140 nM. Ionomycin induced an increase in [Ca2+](i) to well above 750 nM. Manganate reduced Ca2+-dependent fluorescence to virtually zero. Our main conclusion is that changes in [Ca2+](i) can be monitored and quantitatively determined in vivo.

Original languageEnglish
Pages (from-to)H1652-H1662
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Issue number5 44-5
Publication statusPublished - Nov 1 1998



  • Indo 1-acetoxymethyl ester ratiometric method
  • Intravital microscopy
  • Ionomycin
  • Ischemia-reperfusion

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

Cite this

Tóth, A., Ivanics, T., Ruttner, Z., Slaaf, D. W., Reneman, R. S., & Ligeti, L. (1998). Quantitative assessment of [Ca2+](i) levels in rat skeletal muscle in vivo. American Journal of Physiology - Heart and Circulatory Physiology, 275(5 44-5), H1652-H1662.