Design and use of an "optrode" for optical recordings of cardiac action potentials

Michel Neunlist, Sha zhou Zou, Leslie Tung

Research output: Contribution to journalArticlepeer-review

40 Scopus citations


An optical method was used to measure action potentials from frog ventricle, in vitro, under normal physiological conditions with 0.5-1 mM Ca2+ Ringer's solution. The approach presented in this paper involves a portable fluorimeter coupled to a multimode optical fiber running into a glass pipette ("optrode") to carry both excitation light to and fluorescence from the ventricle stained with the voltage sensitive dye di-4-ANEPPS. A suction technique was used to stabilize the optrode-tissue interface, significantly reducing motion artifacts from the beating ventricle. The typical fractional change in fluorescence intensity for an action potential was -9%. The optical recordings faithfully reproduced membrane action potentials as measured with microelectrode recordings. To confirm further the validity of our method we studied the effect of an increasing stimulation rate on the optical action potential. The amplitude of the action potential did not increase, and the change in action potential duration was similar to published results obtained with microelectrode recordings, suggesting that our optical action potentials are relatively free of motion artifacts. Finally, our optical recordings suggest that during anodal and cathodal point stimulation, the time course of membrane potential differs from that predicted simply by a passive cable model.

Original languageEnglish (US)
Pages (from-to)611-617
Number of pages7
JournalPflügers Archiv European Journal of Physiology
Issue number5-6
StatePublished - Apr 1 1992


  • Anodal stimulation
  • Cathodal stimulation
  • Frog heart
  • Motion artifacts
  • Voltage sensitive dyes

ASJC Scopus subject areas

  • Physiology
  • Clinical Biochemistry
  • Physiology (medical)


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