CCAP, Proc, or combinations of both does not modulate short-term synaptic plasticity measured with large presynaptic voltage steps. A, B, Sample experimental traces showing the five postsynaptic currents (with mean amplitude Amp1–Amp5) in response to a set of five presynaptic voltage steps from −60 mV to −20 mV in control and in the presence of either modulator, for the LP to PD (A) and PD to LP (B) synapses. C, Short-term synaptic plasticity was quantified as Amp5/Amp1. This ratio did not change from control to different concentrations of individual neuromodulators or co-modulation. (LP to PD: from control to either CCAP or Proc to co-modulation, F(5,25) = 0.889, p = 0.497 and F(5,25) = 1.19, p = 0.344; PD to LP: from control to either CCAP or Proc to co-modulation, F(5,25) = 1.59, p = 0.199 and F(5,25) = 2.02, p = 0.111. n = 6 for all; all measurements one-way RM-ANOVA).