This volume consists of a collection of 45 papers, most of which were presented at an international symposium held in Helsinki in August 1970. Most of the contributors are authorities in the field. As the title implies, the papers are broadly concerned with the visualization of neurotransmitter agents in nerve cells and the morphological characterization of the specialized subcellular machinery subserving their synthesis, storage, and release. Considerable space is given to considerations of methodology at both the light and electron microscopic level, including advances in the now familiar formaldehyde-induced fluorescence technique for catechol and indolamines, autoradiographic methods for identifying radioactive isotopelabeled transmitters in nerve cells, histochemical techniques for identifying cholinergic neurons, and the recent application of immunohistological methods to studying transmitter function. There are several excellent papers dealing with the yet unresolved problems of the origin and categorization of vesicles.
The majority of the papers are concerned with catecholamines, primarily