Fig. 7.
Presynaptic depolarization, presynaptic changes in Ca fluorescence, and associated inhibitory postsynaptic potential are correlated in heart interneurons. Simultaneous recordings of electrical activity (Vm) and presynaptic changes in Ca fluorescence (ΔF, at the site indicated on theinset), in a pair of oscillator interneurons.A, The preparation was bathed in 0 mmNa+/5 mm Ca2+ saline, and an increasing series of depolarizing current pulses was injected into the presynaptic cell. Changes in Ca fluorescence (ΔF) were recorded at 4–7 Hz. B, Expanded section of traces inA marked with bar.