Stem cells are proposed to play a potential role in organ repair and regular organ function. Especially CD117^(pos) cells have a beneficial influence on cardiac regeneration. Additionally the AT₂ receptor activation has anti-inflammatory properties and might induce differentiation in injured tissues in situ. Stem cells were isolated from bone marrow of mice with induced myocardial infarction. Using MACS and FACS techniques, CD117^(pos) AT₂R^(pos) cells were purified and cultured for 4d. Patch-clamp was performed undr whole cell conditions. In order to identify inactivating voltage- and time-dependent current components, the holding potential was chosen –90 mV or –10 mV with each 500 ms lasting test potentials ranging from –80 mV to +50 mV. Using potassium pipettes, inward rectifying currents were observed in the voltage range negative to –50 mV. Between –50 mV and +20 mV the input resistance was very high (2–4 Gohm) and increased at potentials positive to +20 mV (3–5 Gohm). Time dependent inward current, which could stand for the activation of voltage dependent calcium currents, was not detected. The current elicited from holding potentials of –90 mV was substantially the same as that evoked from a holding potential of –10 mV, indicating the absence of delayed rectifier (IK_dr).Using caesium pipettes and barium (2.5–30 mM) as the charge carrier instead of calcium, did not unmask any time and voltage dependent inward current.

Conclusion: 

Features of 4d cultured CD117^(pos) AT₂R^(pos) stem cells make it unlikely that these cells produce action potentials and voltage triggered calcium influx. It is more likely, that calcium influx is maintained by non-voltage dependent cationic channels.