Fig. 8. Effect of injury on proportion of neurons that respond to capsaicin with an increase of cytosolic calcium. The threshold defining a sensitive neuron was a 50% increase of fluorescence ratio during 100 nm capsaicin administration. Control neurons were compared with neurons from the L4 dorsal root ganglion (SNL4) and L5 ganglion (SNL5) after L5 and L6 spinal nerve ligation. Number of neurons for each group is shown in the bars . ** P < 0.01, *** P < 0.001.