Epidemiological studies have revealed nicotine's surprising protective effect in Parkinson's disease (PD). Interestingly, this protection appears only preventative, as nicotine shows no therapeutic benefits after PD diagnosis. Here, we evaluated the effects of chronic nicotine on two brainstem populations known to selectively degenerate in PD: substantia nigra pars compacta (SNc) dopaminergic neurons and pedunculopontine (PPN) cholinergic neurons. Chronic nicotine decreases activity levels of SNc neurons, depolarizes rostral PPN neurons, and enhances sustained firing capability in caudal PPN neurons. Notably, this is the first study to assess whether chronic nicotine alters the physiology and dendritic morphology of these vulnerable subpopulations. These cellular insights uncover potential mechanisms for promoting neuronal resilience in neurodegenerative diseases.
Chen et al. (Sat,) studied this question.