Fig. 7. Inhibition of excitatory junction potentials (EJPs) by the opener inhibitor (OI) depends on interstimulus interval. A series of recordings from a single muscle fiber is shown; each trace is the average of six trials. In each recording, OI is stimulated at the time indicated by the arrow, the opener excitor (OE) was stimulated at an interstimulus interval indicated to the left of each trace. Note that the delay is preceded by a negative sign if OE is stimulated before OI. Scale bar, 2.5 mV, 250 ms.