Vector injection in sciatic nerve causes only mild stress response in innervating neurons. Sciatic nerve was injected with HGP0-ICElacZ (a, d) or HGP0-lacZ amplicon (b, e) vectors and neuronal stress assessed by immunocytochemistry for ATF3 (a, b) and GAP-43 (d, e) 7 days later. The DRG from an animal receiving no vector injection is shown (c, f) for comparison. Examples of cells with upregulated ATF3 and GAP-43 are indicated with arrow heads. Scale bars: 100 µm.