GDNF and injury: Systemic administration of the glial cell line-derived neurotrophic factor (GDNF) family ligand (GFL) artemin (ARTN) can have protective effects in animal models of experimental nerve-injury, as measured by increased regeneration and functional recovery, and transient reductions in hyperalgesia following nerve-injury (Boucher et al., 2000; Gardell et al., 2003; Harvey et al., 2010; Takasu et al., 2011; Hedstrom et al., 2014; Wang et al., 2014).