Table 2.

Genetic tools in locomotion and respiration

Method	Target of Action	Effect	Inducer	Caveats	Advantages
Knock out (a–f)	gene inactivation	loss of protein function	-	often perinatal lethal can affect multiple cell types respecification of cells adaptation possible	many mouse mutants available
DTA (b,g)	inhibition of RNA translation	cell death	-	presynaptic cells may be affected by loss of their target adaptation possible not neuron specific	highly efficient method to remove one defined population ablation is easy to monitor
TeNT (h)	cleavage of VAMP-2 synaptic protein	silencing (synaptic transmission)	-	adaptation possible silencing difficult to assess	targeted cells remain in the circuit affects only neuronal cells
AlstR (b, h)	activation of GIRK channel	silencing (hyperpolarisation)	Alst (peptide)	can not be injected systemically (does not cross BBB) desensitization after prolonged exposure	inducible/reversible within minutes local effect by intrathecal application of Alst allows analysis of short term effects allows analysis in adult mice
ChR2 (i)	expression of light sensitive cation channel	activation (depolarisation)	Blue Light	high expression levels required few transgenic mice successfully generated light penetration into deep tissue	inducible/reversible within milliseconds local excitation possible allows analysis of short term effects

DTA, Diphteria Toxin A; DTR, Diphteria Toxin Receptor; TeNT, Tetanus toxin light chain; AlstR, Allatostatin Receptor; Alst, Allatostatin; ChR2, Channelrhodopsin 2; BBB, blood brain barrier; GIRK, G-protein-coupled inwardly-rectifying potassium channel; VAMP-2, vesicle-associated membrane protein 2 (synaptobrevin2). a, (Lanuza et al., 2004); b, (Gosgnach et al., 2006); c, (Pagliardini et al., 2008); d, (Rose et al., 2009); e, (Dubreuil et al., 2009); f, (Wallen-Mackenzie et al., 2006); g, (Crone et al., 2008); h, (Zhang et al., 2008); i, (Hagglund et al., 2010).