The cholinergic nervous system and lung diseases: dual inflammatory and anti-inflammatory effects

Pulmonary diseases are among the most common diseases that are associated with the disability of patients and, in severe cases, with high mortality. In recent years, the role of the autonomic nervous system in aggravating or modulating the inflammatory reactions of various body organs, including the lungs, has been discussed. Some reports indicate the anti-inflammatory role of the parasympathetic nervous system, while other studies have suggested the inflammatory role of this system. Also, some studies highlight the role of the spleen in reducing inflammation, while others have considered the role of the spleen in exacerbating inflammation and tissue damage. Meanwhile, the role of alpha-7 nicotinic receptor in spleen and lung is controversial. The contradictory results of these studies can be attributed to the differences in the timing of stimulation and inhibition of the parasympathetic nervous system, the severity of the lung injury, and the type of pathogenic and non-pathogenic factors in different animal models of lung injury. In this review, we have discussed the role of the parasympathetic nervous system, spleen and a7 nicotinic acetylcholine receptor in the pathogenic and non-pathogenic lung diseases and the underlined mechanisms. According to the data of this article, more studies are needed to clarify the inflammatory or anti-inflammatory role of the cholinergic system in various inflammatory lung diseases.
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