[Pure autonomic failure and acetylcholine: historical and current aspects]

The discovery of acetylcholine was closely related to research on the autonomic nervous system. At the onset of the twentieth century, John Newport Langley (1852-1925), a patriarch of modern autonomic research, classified the autonomic nervous system into the sympathetic, parasympathetic, and enteral systems, proposed the concept of preganglionic and postganglionic autonomic nerves, and suggested the presence of a "receptive substance" allowing the interaction of postganglionic nerve terminals and effector visceral organs. Around the same time, Henry Hallett Dale (1875-1968) revealed the pharmacological properties of acetylcholine, and he and his colleague, Wilhelm Feldberg (1900-1993), demonstrated that acetylcholine acts as a mediator of nerve impulses across nerve junctions (synapses) between nerves (sympathetic ganglia), and between the vagus nerve and heart (parasympathetic nerve terminals). On the other hand, Bradbury and Eggleston first described 3 patients with orthostatic hypotension in 1925, introducing the term "idiopathic orthostatic hypotension". However, this term was used loosely. Therefore, Roger Bannister proposed "pure autonomic failure" as the term for idiopathic orthostatic hypotension without other neurological symptoms. Recently, autoimmune autonomic ganglionopathy associated with anti-ganglionic acetylcholine receptor antibodies has attracted attention as a differential diagnosis of pure autonomic failure, which is characterized by Lewy body pathology.