Perfusion of substance P (15 μM) had no effect on the amplitude or slope of the fEPSP recorded from the CA1 region of the rat hippocampal slice. (a) Example synaptic response recorded from a single slice using a single stimulus of the Schaffer collateral-commissural fibres every 30 s. The response on the left was recorded under control conditions whereas the trace on the right was recorded in the presence of substance P (15 μM). (b) and (c) Pooled time course data showing the lack of effect of substance P on the slope (b) and amplitude (c) of the fEPSP. Points represent mean ± s.e.m., n = 4. Scale bar represents 0.5 mV and 10 ms.