Electroablation applied to spinal cord injury in larvae and tissue damage in the caudal fin of adult fish. (a-c) 72 hpf TgBAC (neurod:EGFP) transgenic larvae were subjected to spinal cord injury. (a) The intact spinal cord before electroablation is shown. The dotted lines show the outline of the larva. (b) A 1 second 25 μA pulse was applied in the spinal cord (arrowhead), leaving a gap and rendering larvae unable to move their tails. (c) The regenerated spinal cord at 5 dpi. (d-i) Damaging of different tissues in caudal fin of adult fish by application of a 2 second 25 μA pulse of current. (d-f) Induction of neutrophil recruitment in the caudal fin of adult TgBAC(mpx:GFP) transgenic fish. A large number of neutrophils recruited to the site of damage is observed by 2 hpi (f). (g-i) Tg(flia:EGFP) transgenic adult fish in which blood vessels are labeled in green were subjected to electroablation in a single blood vessel (h), leaving a gap in it, as shown in (i) (see inset for higher magnification). (j-l) Caudal fin neuromast electroablation in sqet20 transgenic fish, which possess neuromasts labeled in green. (j) Intact fin neuromasts are shown. Within the line of five neuromasts shown in the inset, note positioning of the microelectrode over the second pair of neuromasts (k). (l) After electroablation, the pair of neuromasts has been destroyed and a gap in the GFP pattern can be observed at that position (see inset for details). Note that the electrode is easily observable during electroablation facilitating its positioning (e, h and k). Scale bars: a-c, 100 μm; d-l, 500 μm; and i, j, and l insets 100 μm. dpi, days post-injury.