A: Representative trace illustrating the depolarization of resting membrane potential following the bath application of BaCl2 (200 μM) in a pacemaker spinal projection neuron. Dotted line indicates the initial resting membrane potential. Scale bar = 10 mV, 5 s. B: The degree of membrane depolarization evoked by external Ba2+ was similar between the types of projection neuron (n = 21 in each group; Drug: F(1,40) = 33.25, p < 0.0001; Cell type × Drug Interaction: F(1,30) = 0.234, p = 0.631; RM two-way ANOVA; **p = 0.001, ***p = 0.0001, Sidak’s multiple comparisons test). C: Membrane resistance was increased by the presence of extracellular Ba2+ in both pacemakers and non-pacemakers (n = 13–19 per group; Drug: F(1,30) = 26.78, p < 0.0001; Cell type × Drug Interaction: F(1,30) = 0.437, p = 0.514; RM two-way ANOVA; *p = 0.013, ***p = 0.0002, Sidak’s multiple comparisons test).