Work

At the beginning of the 20th century, it was known that the nervous system’s signals are conveyed with the help of electrical impulses. However, it was unclear whether the signals were also conveyed by chemical substances. In 1914 Henry Dale found that acetylcholine generated stimuli in part of the nervous system, the parasympathetic nervous system, which has a dampening effect on heart activity and other functions. After Otto Loewi demonstrated acetylcholine’s function as a messenger between nerves and organs, Dale and other researchers refined the understanding of acetylcholine’s role in the nervous system.