Acetylcholine, a Ubiquitous Signalling Substance

This book presents an up-to-date review concerning acetylcholine, a messenger substance which is produced transiently in practically all living organisms, from bacteria to human beings. High acetylcholine concentrations have been encountered in growing parts of plants, in the royal jelly of bees, and in the human placenta. In vertebrates, many non-neuronal cells, such as epithelial cells, endothelial cells, immune cells or spermatozoids, secrete acetylcholine in response to specific signals.Acetylcholine is better known as a neurotransmitter substance, supporting synaptic transmission in the central and autonomic nervous systems. Transmission in these places is a point-to-point process which is relatively rapid and shows many anatomical and physiological variations, according to synapses and animal species. Much more rapid is transmission in giant and specialised synapses, such as the neuromuscular junctions and their homologues, in the electric organs of certain fish. The mechanisms of acetylcholine release in these ultra-rapid junctions have been revisited in recent decades and the picture has completely changed.As the book shows, acetylcholine signalling (also called cholinergic signalling) is of particular physiological and toxicological importance, since it can be perturbed by many natural or synthetic substances.