Figure 1

Substance P changes the excitability of a sub-population of DRG neurons. A. Action potentials generated by current injection in a DRG neuron before (upper trace) and during treatment with 2 μM Substance P (lower trace). The broken line indicates 0 mV. Resting potential was -55 mV in control and -50 mV in Substance P. Current injection was 120 pA in control and 80 pA in Substance P. B. Input-output relationship for the same cell when stimulated with 1-4 times its threshold current (control: 30 pA, Subtance P: 20 pA).