Spinal cord injury leads to flaccid paralysis resulting from the loss of descending serotonergic modulation. Murray et al. demonstrate that spontaneous recovery of motoneuron excitability is associated with alternative mRNA editing and increased expression of constitutively active 5HT2C serotonin receptors. Activation of these receptors leads to large persistent calcium currents, sustained muscle contractions and restoration of locomotion. However, in the absence of descending modulation from the brain, this leads to spasticity. Inhibiting constitutive 5-HT receptor activity is effective in reducing spasticity in rats and humans following spinal cord injury.
- Katherine C Murray
- Aya Nakae
- Karim Fouad
