Channel:
Cells:

Application NoteINa, ICa , IK
ES cell-derived
cardiomyocytes
Port-a-Patch®

Tools:

Recordings of Action Potentials in Mouse ES
Cell-Derived Cor.At® Cardiomyocytes on
Nanion's Port-a-Patch®
The electrophysiology team at Nanion Technologies GmbH, Munich, Germany.
Axiogenesis AG, Cologne, Germany.

Introduction

Results

To provide scientists in basic or applied cardiology andCurrent responses in the voltage clamp mode of Cor.At®

toxicology with a standardized and pure cardiac myo-cardiomyocytes are shown in Figure 1. Figure 2 shows thecyte model with functional expression of all essential car-corresponding current-voltage relationships.

®

diac ion channels, Axiogenesis has developed Cor.Atcardiomyocytes. These mouse embryonic stem cell de-1.0

rived cardiomyocytes are ready to use and 99.9 % pure0.8

without contamination by other cell types. Using the Port-

0.60.2

been shown to functionally express at least three essen-

0.0

100 ms500 pA

-0.5-200-1.0-300

tial cardiac currents INa, ICa, and IK, and to exhibit typicalIK

0.0-100

0.4a-Patch®, Cor.At® cardiomyocytes have experimentallycardiac action potentials.

0.50-400mV

40-40mV

40-50mV

50

Figure 2:
Current-voltage relationship of the whole cell currents shown in Figure
1. K-outward current (left), Ca-channel derived current (middle) andNa-current (right).

:KHQ WKH FRQÀJXUDWLRQ ZDV VZLWFKHG WR FXUUHQW FODPSmode, the cells showed typical cardiac action potentials(Fig. 3).
50 ms

ICa-40 pA

200 pAI(memb)
0 mV

INa

1s

0.5 nA

10 ms

Figure 1:
Whole cell current as recorded in the voltage clamp mode reveal all
three cardiomyocyte typical ion channels. K-channel (top), Ca-channel derived current (middle) and Na-current (bottom).

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Figure 3:
Action potentials in Cor.At® cardiomyocytes. The action potentials
were elicited by depolarisation from a holding current I(memb) to -40 pA
for 350 ms with a sweep interval of 5 s.

Application Note
The Human Ether-a-go-go Related Gene hERG encodes

TTX is a Na-channel blocker and, after application of 20

a K-channel, which is considered responsible for repolari-µM to the external recording solution, the action potentials

zing IKr current in the human cardiac action potential. Theshowed a decrease of the maximum as well as a slower

hERG blocker Dofetilide induced a prolongation of thedepolarisation of the action potential.

action potential (Fig. 4 and Fig. 5 A), which gives a hint to
the presence of the mouse analog of hERG-channels inCor.At® cardiomyocytes. The effect proved to be reversi-Summary

ble upon washout of the drug.

Cor.At® cardiomyocytes display typical cardiac ion

Achannel activity and action potentials. The hERG blocker-40 pA

Dofetilide induced a prolongation of the action potenti-I(memb)al, the Na-channel blocker TTX leads to a decrease of theBcontrol

Dofetilide,
1µM

action potential and to a slower depolarisation. Both ef-washout

fects were reversible upon washout of the drugs.

0 mV

150 ms

The results indicate that Cor.At® cardiomyocytes exhibit
primary cell-like qualities, and that these electrophysiolo-Figure 4:
A Current clamp protocol that was used for the stimulation of action potentials as seen in B. B Action potential in control solution (left), after theexternal application of 1 µM Dofetilide (middle) and after washout (right).

gical properties can be observed with Nanion´s planar

Amode. The measurements shown here were recorded

Bcontrolcontrol
TTX, 20 µM

Dofetilide, 1 µM

patch clamp technology. The technology allows recordings in the voltage clamp as well as in the current clamp
with the one channel patch clamp device from Nanion,
the Port-a-Patch®7KLVLVWKHÀUVWGHPRQVWUDWLRQRIDFWLRQ

150 mspotential recordings on a planar patch clamp system.
Since the basic technology is the same also for the higher

washout

washout

throughput devices from Nanion, we propose that these

Figure 5:
A Overlay of the traces as seen in Fig. 4 B. Note the reversible prolongation of the action potential in the presence of the hERG blocker Dofetilide.
B Application of the Na-channel blocker TTX (20 µM) leads to a reversible
decrease of the maximum, as well as a slower depolarisation, of the action
potential.

recordings could also be scaled up using the Patchliner®.

Methodsaccording to Nanion’s standard procedure for theHere, 8 channels in parallel could be recorded simultaneously.

Port-a-Patch®. K-channel currents were elicited using 500

Cells

ms voltage steps from a holding potential of -80 mV to -60

Cor.At® cardiomyocytes (Axiogenesis AG, Cologne, Germany); www.axiogenesis.com, email: info@axiogenesis.
com

mV up to +60 mV (20 mV increments, sweep interval 15 s)
followed by a step back to the holding potential. Ca-channel currents were elicited using 200 ms voltage steps from aPatch Clamp solutionsholding potential of -80 mV to -80 mV up to +60 mV (20 mVExternal solution for Ca-channel recordings: 145 mM TEA-increments, sweep interval 5 s) followed by a step back toCl, 20 mM BaCl2, 10 mM HEPES, 10 mM Glucose, pH 7.35.

the holding potential. Na-currents were elicited using vol-External solution for K- and Na-channel recordings: 140tage steps from a holding potential of -80 mV to -60 mV up

mM NaCl, 4 mM KCl, 1 mM MgCl2, 2 mM CaCl2, 5 mMto +60 mV (10 mV increments, sweep interval 1 s) for 20 ms

D-Glucose monohydrate, 10 mM Hepes /NaOH pH 7.4.

followed by a step back to the holding potential.

Internal solution: 50 mM KCl, 10 mM NaCl, 60 mM K-Fluoride, 20 mM EGTA, 10 mM Hepes /KOH, pH 7.2.
Electrophysiology
Whole cell patch clamp recordings were conducted
Nanion Technologies GmbHphone +49 89 218997972

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fax80335 Munich, Germany

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