A new development in the relief of spasms related to amyotrophic lateral sclerosis

Paralysis is accompanied by other symptoms, which can be highly disabling on a daily basis. Spasms (or spasticity) are an exaggerated muscular response to a stimulus; they produce long and involuntary muscle contractions, coupled with pain. Spasticity is frequently observed in ALS. Until now, it was attributed to the loss of central motor neurons.

In this study, Inserm researchers have shown that these spasms are, in fact, linked to the degeneration of another type of serotonin-producing neurons located on the brain.

They have observed - both in patients with ALS and in a transgenic mouse model - that serotonergic neurons waste away as the disease develops and that serotonin levels in the spinal cord sharply decreased before the motor-related symptoms appeared.

Furthermore, some molecules active against serotonin receptors eliminate spasms in transgenic mice suffering from ALS. This research demonstrates that neuron degeneration in ALS is not limited to the motor system in its strictest sense. For Luc Dupuis "molecules acting on serotonin receptors 5-HT2B and C could be antispastic for ALS patients over the long-term".

More information: Degeneration of serotonin neurons in amyotrophic lateral sclerosis: a link to spasticity, brain.oxfordjourna… aws274.short

Provided by Institut National de la Sante et de la Recherche Medicale