Synaptic Variability Introduces State-Dependent Modulation of Excitatory Spinal Cord Synapses

Figure 8

The effects of high Mg²⁺ Ringer on substance P-evoked synaptic modulation. Graphs show the lack of a significant effect of high Mg²⁺ on the EPSP amplitude (a) but a significant increase in the PP ratio (b), indicative of a reduction in release probability. (c) Graph showing the EPSP half-width at connections where the low frequency-evoked EPSP amplitude was potentiated or depressed by substance P.

(a)

(b)

(c)