Firing patterns in SG neurons in wild-type and GluR5-/- mice. (A) Diagram indicating the placement of recording electrodes in spinal dorsal horn slices. (B) Confocal image of a SG neuron in a spinal slice loaded with 0.1% lucifer yellow. Scale bar: 8 μM. (C) Firing patterns of SG neurons in wild-type mice. When injected with current steps from -20 pA to +100 pA in 800 ms (right bottom), neurons were displaying delayed firing, tonic firing, initial bursting, phasic bursting, and single spike patterns.