The Symposium on "Ion Selective Microelectrodes and Their Use in Excitable Tissues" was held in Prague from July 8-11, 1980. It was organized by the Institute of Physiology of the Czechoslovak Academy of Sciences as a satellite symposium of the XXVIII Interna tional Congress of Physiological Sciences in Budapest. Sixty parti cipants met for three days in the historical setting of the Strahov Monastery. The informal and relaxed atmosphere of the scientific sessions, together with the social programme made the meeting a success and helped to cement old friendships and to form new ones. The organizers were happy to welcome as participants representatives from most of the laboratories working with ion-selective microelectrodes (ISMs) in the world. Neurophysiological research with liquid ion-exchanger ISMs in the Prague laboratory was started as early as 1971 due to the fact that one of us (P. H. ) had the opportunity of learning the technique directly from Dr. J. L. Walker in Salt Lake City. It was thanks to his patience and, later, his courtesy in providing us with the liquid ion-exchanger for potassium and silicone that we were able to get a start in what turned out to be, in a year or so, very strong international competition. This volume contains the papers presented at the Symposium. It is divided according to the actual sessions with names of the chair men, who helped the organizers to make the Symposium a real success."

Stability of the internal environment in which neuronal elements are situated is unquestionably an important prerequisite for the effective transmission of information in the nervous system. During the past decade our knowledge on the microenvironment of nerve cells has expanded. The conception that the microenvironment of neurones comprises a fluid with a relatively simple and stable composition is no longer accepted; the microenvironment is now envisaged as a dynamic structure whose composition, shape, and volume changes, thereby significantly influencing neuronal function and the trans mission of information in the nervous system. The modern conception of the neuronal microenvironment is based on the results of research over the last 20 years. The extracellular space (ECS) is comprehended not only as a relatively stable microenvironment containing neurones and glial cells (Bernard 1878), but also as a channel for communica tion between them. The close proximity of the neuronal elements in the CNS and the narrowness of the intercellular spaces provides a basis not only for interaction between the elements themselves, but also between the elements and their microenvironment. Substances which can cross the cell membranes can easily find their way through the microenvironment to adjacent cellular elements. In this way the microenvironment can assure non-synaptic com munication between the relevant neurones. Signalization can be coded by modulation of the chemical composition of the ECS in the vicinity of the cell membrane and does not require classic connection by axones, dendrites, and synapses.

In mammals the glial (or glue) cells contribute some 50% of the volume of the brain. In contrast to the traditional view that they have a purely physically supportive role, research in the last three decades has shown that glia interact morphologically, biochemically and physiologically with neurons during changes in behaviour. The evidence suggests that glia may modulate neuronal activity and thereby influence behaviour. This 1998 book was the first to describe and discuss these neuronal-glial interactions in relation to behaviour. A distinguished set of authors discuss these interactions from a number of viewpoints, and the book will familiarise neuroscientists, zoologists, physiologists and psychologists with the new knowledge of how neurons and glial cells interact with each other to affect behaviour.