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Neurophotonics • Open Access

Optical recording of calcium currents during impulse conduction in cardiac tissue
Author(s): Florian Jousset; Stephan Rohr

Paper Abstract

We explore the feasibility of obtaining a spatially resolved picture of Ca2+ inward currents (ICa) in multicellular cardiac tissue by differentiating optically recorded Ca2+ transients that accompany propagating action potentials. Patterned growth strands of neonatal rat ventricular cardiomyocytes were stained with the Ca2+ indicators Fluo-4 or Fluo-4FF. Preparations were stimulated at 1 Hz, and Ca2+ transients were recorded with high spatiotemporal resolution (50  μm, 2 kHz analog bandwidth) with a photodiode array. Signals were differentiated after appropriate digital filtering. Differentiation of Ca2+ transients resulted in optically recorded calcium currents (ORCCs) that carried the temporal and pharmacological signatures of L-type Ca2+ inward currents: the time to peak amounted to ∼2.1  ms (Fluo-4FF) and ∼2.4  ms (Fluo-4), full-width at half-maximum was ∼8  ms, and ORCCs were completely suppressed by 50  μmol/LCdCl2. Also, and as reported before from patch-clamp studies, caffeine reversibly depressed the amplitude of ORCCs. The results demonstrate that the differentiation of Ca2+ transients can be used to obtain a spatially resolved picture of the initial phase of ICa in cardiac tissue and to assess relative changes of activation/fast inactivation of ICa following pharmacological interventions.

Paper Details

Date Published: 13 February 2015
PDF: 9 pages
Neurophoton. 2(2) 021011 doi: 10.1117/1.NPh.2.2.021011
Published in: Neurophotonics Volume 2, Issue 2
Show Author Affiliations
Florian Jousset, Univ. Bern (Switzerland)
Stephan Rohr, Univ. Bern (Switzerland)

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