Neurotransmitter release from presynaptic terminals can be recorded as EPSCs in CNS.Although peripheral nerves modulate heart function, little is known about real-time recordings of cardiac neurotransmitter release.Here we report a novel method, cardiac slices of electrochemical recordings (cSEC), to record norepinephrine (NE) release from the sympathetic nerve terminals in rat/mouse cardiac slices using micro carbon fiber electrode (CFE).