The apparent importance of constitutively active 5-HT receptors in the recovery of locomotor activity and motoneuron excitability after spinal cord injury (Fouad et al., 2010; Murray et al., 2010) is considered one of the most significant contributions to the understanding of the fact that locomotion reappears after spinal cord injury, despite removal of the endogenous ligand, 5-HT, as a result of SCI. Here, HTR5A is linked to spinal cord injury.