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Figure 1 | Molecular Pain

Figure 1

From: Substance P-driven feed-forward inhibitory activity in the mammalian spinal cord

Figure 1

Feed-forward inhibitory activity in the absence of glutamatergic driving force. a, Rat spinal cord slice with attached dorsal root. A portion of the root is sucked into a stimulation electrode. Recordings were made in lamina V. b, Five consecutive traces show EPSCs evoked by electrical stimulation (top). The EPSCs were abolished in the presence of 20 μM CNQX plus 50 μM APV (bottom). Vh = -60 mV. c, In the same cell, stimulation evoked IPSCs (top), which were abolished in the presence of 20 μM CNQX and 50 μM APV (bottom). Vh = -10 mV. d, In the same cell, trains of stimulation (20 Hz for 1 min) increased IPSCs in the presence of 20 μM CNQX plus 50 μM APV. Top trace was IPSCs recorded before and after electrical stimulation. The bottom 3 traces are at an expanded scale. Vh = -10 mV. e&f, Time course of IPSC frequency (e) and amplitude (f). Horizontal bars indicate stimulation. Overall, at peak responses, IPSC frequency increased to 376 ± 47% of control (n = 5, P < 0.05); IPSC amplitude increased to 228 ± 74% of control (n = 5, P < 0.05). Similar results were also obtained in the presence of 3 mM kynurenic acid (see Figure 2c). g–j, Capsaicin-induced increases in inhibitory activity in the absence of glutamatergic driving force. g, The top trace is a continuous recording of IPSCs from a rat lamina V neuron before and following the application of 2 μM capsaicin in the presence of 3 mM kynurenic acid. The bottom 2 traces are at an expanded scale. h, The time course of IPSC frequency in (g). bin width: 10s. i&j, Capsaicin-induced increases in IPSC frequency (i) and amplitude (j) recorded from 6 rat lamina V neurons in the presence of 3 mM kynurenic acid.

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