Popoli, Reynaldo2025-07-282025-07-282025-07-25https://hdl.handle.net/10222/85235Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease with limited therapeutic options. This work investigates the potential of targeting cholinergic signalling as a treatment avenue using the mSOD1G93A mouse model of ALS. Building upon prior findings that genetically silencing spinal C-boutons combined with swimming improves disease outcomes, we tested whether chronic administration of pharmacological antagonists could produce similar benefits. Initial experiments with atropine, a non-selective cholinergic antagonist, improved motor function and extended humane endpoint in both swimming and non-swimming ALS mice, suggesting a central role for cholinergic modulation beyond physical activity. Subsequent studies with methoctramine, an M2-selective cholinergic antagonist, showed even greater efficacy, particularly when administered early and independent of exercise. However, methoctramine was ineffective when administered at symptomatic stages, suggesting a critical window of administration for its beneficial effects. Notably, methoctramine was undetectable in cerebrospinal fluid after its administration, pointing to peripheral mechanisms of action. EMG recordings and electrophysiological analyses revealed enhanced neuromuscular transmission following methoctramine treatment, likely due to increased acetylcholine release at the neuromuscular junction. The improvements seen in mSOD1G93A mice following chronic administration of methoctramine may also involve Schwann cell proliferation and enhanced repair via antagonism of the M2 receptor. Since methoctramine was ineffective when administered at symptomatic stages, this suggests limited regenerative potential once denervation and Schwann cell senescence are established. Overall, our work shows methoctramine’s capabilities in slowing ALS disease progression, as well as shedding some light on some of the potential mechanisms behind these effects. We hope that these findings will advance future research efforts and guide the development of therapeutic strategies targeting the mechanisms examined in this thesis, in the context of ALS and other motor neuron disorders.enNeuroscienceALSCholinergic antagonistMethoctramine