Let’s not forget about the vagus and other updates on recent autonomic research

Excerpt

Autonomic failure is a prominent feature of synucleinopathies such as Parkinson disease (PD), dementia with Lewy bodies, multiple system atrophy, and pure autonomic failure (PAF). In these conditions, misfolded alpha-synuclein accumulates in neuronal cells and eventually leads to cell death. Misfolded alpha-synuclein can also spread from cell to cell in prion-like fashion [1], and researchers have demonstrated in animal models that misfolded alpha-synuclein can spread from the gastrointestinal system to the brainstem via the vagus nerve. In support of this hypothesis, resection of the vagus nerve in animals seems to halt the progression of alpha-synuclein spread [2]. Taken together, these findings raise the possibility of the vagus nerve as a key pathway for alpha-synuclein progression from the gastrointestinal system to the central nervous system in humans. While a prospective study of vagus nerve transection in humans might not be feasible due to ethical reasons, several groups have examined this connection by retrospectively evaluating patients who had already undergone vagotomy for other conditions. Although not routinely performed currently, vagotomies were a relatively common procedure for the treatment of peptic ulcer disease several decades ago. …