Fig. 2

Lumbar DRG extraction. a Using insect pins placed through two of the soft, white vertebral discs towards each end of the hemi-segment, affix the lumbar spinal column to the Sylgard dish with the spinal canal facing outwards. R, rostral; C, caudal, D, dorsal; V, ventral (orientation maintained in all panels). b Remove the bisected spinal cord. Note that the centrally projecting axons emanating from DRG can be seen and used to trace the location of the ganglia (arrow identifies lumbar level 1 [L1] DRG). c DRG reside within dorsal intervertebral foramina in the spinal canal, level with each disc (arrows). When the column is cut in half at the most caudal rib pair (see Additional file 1), the thoracic level 13 (T13) DRG is the first ganglion found at the rostral end of the lower column half, followed by L1 to L5. d, e Remove the meninges that line the spinal canal, covering the DRG. This is best done starting at one end and peeling back towards the other (left to right, here). The arrow highlights the membrane clasped by forceps. f T13 to L5 DRG are easily visible in situ. g–j Pick up individual DRG using their distally projecting (i.e. towards the dish) axon bundle, found within each foramen (L2 DRG removed, here). Pay attention to avoid touching the DRG directly. k–m Identify and remove axons from extracted DRG. n Lumbar DRG increase in size from L1 to L4. L4 is considerably larger than L5, as are the associated axon bundles. Identification of L4 DRG is a useful way to confirm spinal level. o Once all required ganglia have been removed, the column can be discarded. For videos of steps a-j and k–o see Additional files 2 and 3, respectively. Scale bars = 5 (a–e, o), 2 (f–j, n) and 1 (k–m) mm