[Serotoninergic system morphofunctional aspects in control of postural and locomotion function]

Area of Science:

• Neuroscience
• Spinal Cord Injury Research
• Motor Control

Context:

• The spinal cord can generate locomotor activity independently of brain control.
• The serotoninergic system is a key neuromodulator influencing motor functions.
• Previous research indicates afferent input can activate spinal locomotor mechanisms.

Purpose:

• To investigate the effects of blocking the serotoninergic system on locomotor behavior in rats with complete spinal cord transection.
• To examine the histological impact of serotoninergic system blockade on spinal cord neuronal structure and synaptic organization.

Summary:

• Pharmacological blockade of the serotoninergic system in rats with transected spinal cords led to a depression of motor activity, specifically through the activation of support reactions.
• Histological analysis revealed no adverse effects on neuronal survival or synaptic distribution in L2-L4 segments due to support reaction activation.
• However, serotoninergic system blockade caused cellular alterations in dorsal horn laminae 1-3 and Rexed's lamina 7, along with synaptic redistribution in dorsal horn laminae 1-4.

Impact:

• This study elucidates the critical role of the serotoninergic system in maintaining locomotor activity post-spinal cord injury.
• Findings highlight specific spinal cord regions and neuronal populations affected by serotoninergic modulation, offering potential targets for therapeutic interventions.
• Understanding these neurobiological changes is crucial for developing strategies to restore motor function after spinal cord damage.