TABLE 2.

Effects of the supply (+) or depletion (−) of axonal growth-promoting molecules in the surrounding tissue of sensory (S) or motor (M) fibers.

Molecule	S+	M+	S−	M−
NGF	↑	↓	↓	↑
BDNF	↑	↑	↓
NT3	↑	↑	↓	↓
NT4/5	↑	↑
GDNF	↑	↑
IGF1	↑	↑	↓
IGF2		↑
FGF2	↑	↑
CNTF	↑	↑
PTN	↑	↑

References: NGF: S+, (Apfel, 1999; Höke et al., 2006; Webber et al., 2008; Hoyng et al., 2014; Santos et al., 2016b; Anand et al., 2017); M+, (Wong et al., 1993; Wang et al., 1997; Boyd and Gordon, 2003; Pehar et al., 2004, 2006); S−, (Averill et al., 1995; Suzuki et al., 2016); M−, (Pehar et al., 2004, 2006). BDNF: S+, (Apfel, 1999; Fine et al., 2002; Höke et al., 2006; Allodi et al., 2012; Gordon, 2014; Grosheva et al., 2016); M+, (Funakoshi et al., 1993; Wong et al., 1993; Friedman et al., 1995; Kobayashi, 1996; Apfel, 1999; Al-Majed et al., 2000, 2004; Hammarberg et al., 2000; Terris et al., 2001; Boyd and Gordon, 2003; Allodi et al., 2012; Gordon, 2014; Hoyng et al., 2014; Santos et al., 2016b); S−, (Geremia et al., 2010). NT3: S+, (Apfel, 1999; Santos et al., 2016b; Anand et al., 2017); M+, (Funakoshi et al., 1993; Wong et al., 1993; Apfel, 1999; Hammarberg et al., 2000; Boyd and Gordon, 2003; Allodi et al., 2012; Anand et al., 2017); S−, (Hou et al., 2012; Wang et al., 2015); M−, (Wang et al., 2015). NT4/5: S+, (Apfel, 1999; English et al., 2005, 2011); M+, (Funakoshi et al., 1993; Wong et al., 1993; Friedman et al., 1995; Apfel, 1999; Boyd and Gordon, 2003; English et al., 2005, 2011). GDNF: S+, (Apfel, 1999; Keast et al., 2010; Allodi et al., 2012; Santos et al., 2016b; Anand et al., 2017); M+, (Apfel, 1999; Hammarberg et al., 2000; Boyd and Gordon, 2003; Allodi et al., 2012; Hoyng et al., 2014; Santos et al., 2016b; Anand et al., 2017; Ruven et al., 2018). IGF1: S+, (Kanje et al., 1989; Brushart et al., 2013); M+, (Li et al., 1994; Di Giulio et al., 2000); S−, (Kanje et al., 1989). IGF2: M+, (Brushart et al., 2013). FGF2: S+, (Grothe et al., 2006; Allodi et al., 2012; Brushart et al., 2013; Santos et al., 2016b); M+, (Allodi et al., 2012; Brushart et al., 2013; Santos et al., 2016b). PTN: S+, (Anand et al., 2017); M+, (Mi et al., 2007; Gordon, 2014). CNTF: S+, (Apfel, 1999); M+, (Wong et al., 1993; Apfel, 1999; Hammarberg et al., 2000). Up-oriented arrows (↑) indicate facilitation of the regeneration of these fibers, whereas down-oriented arrows (↓) indicate inhibition. No arrow indicates that this experimental condition has not been tested. Supply of any of the neurotrophic factors to the injured fibers, either sensory or motor, favors the regeneration of both fibers. NGF is the only exception.