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.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.