Journal of neurotrauma
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Journal of neurotrauma · Aug 2014
Randomized Controlled TrialEffects of serotonergic medications on locomotor performance in humans with incomplete spinal cord injury.
Incomplete spinal cord injury (iSCI) often results in significant motor impairments that lead to decreased functional mobility. Loss of descending serotonergic (5HT) input to spinal circuits is thought to contribute to motor impairments, with enhanced motor function demonstrated through augmentation of 5HT signaling. However, the presence of spastic motor behaviors in SCI is attributed, in part, to changes in spinal 5HT receptors that augment their activity in the absence of 5HT, although data demonstrating motor effects of 5HT agents that deactivate these receptors are conflicting. ⋯ Results indicate that neither medication led to improvements in locomotion, with a significant decrease in peak overground gait speed observed after 5HT antagonists (from 0.8±0.1 to 0.7±0.1 m/s; p=0.01). Additionally, 5-HT medications had differential effects on EMG activity, with 5HT antagonists decreasing extensor activity and SSRIs increasing flexor activity. Our data therefore suggest that acute manipulation of 5HT signaling, despite changes in muscle activity, does not improve locomotor performance after iSCI.