1 IN,~ l~ehruarv I t)~'5
84 molecules and mlcro-orgamsms. The ideas are applied to sedimentation and to separation in centnfugation Chapter 5 treats diffusion at e q u t h b n u m which leads to a discussion of the B o l t z m a n n d m t n b u t l o n The results are applied to e q m h b n u m densitygradient s e p a r a t m n The next chapter provides some of the most interesting reading in the book It describes the problems faced by a self-propelled organism, e.g. a swimming bacterium_ A b a c t e n u m has two problems, one is viscosity, which will cause it to stop within less than an A n g s t r o m when its flagellae stop; the o t h e r is rotational diffusion, which causes it inevitably to
lose track of its direction of movement T h e bacterium overcomes this latter hardship by a sequence of 'runs' and 'tumbles', the chemotactlc process that Berg himself first described In 1972_ The Pomson process is used to describe the 'run' times The last chapter treats other r a n d o m walks, including counter-currents and partition chromatography; the latter are analysed using autocorrelatlon functions The book has few weaknesses Some early results are presented without particular motivation, but a chapter or two later they are used The book is suitable for teaching, but no
problems are included_ Certain topics of interest to TINS readers such as electrical potentials and excitable systems are not discussed But the topics that are covered are presented so well that most biologists, both researchers and students, will find reasons to have this slim volume on their bookshelf (or on their desk to keep the whimsical cover in view) I expect that the popularity of this book will soon lead to Its release In paperback
Intracellular Perfusion Excitable Cells
messengers modulate iomc channel actwity, pubhcatlon of Intracellular Perfuston o f Excitable Cells ts timely. T h e editors of the book, Kostyuk and Knshtal, pioneered use of the m e t h o d in the investigation of calcium channels m nerve cells_ The contributors of its seven chapters come from Britain, Japan, the Soviet U n i o n and the U n i t e d States T h o u g h each chapter may be read on its own, the book has a clear overall strategy. It deals first with methods of perfusing giant axons and muscle fibres and then with ways of perfusing smaller nerve cells using either glass or plastic pipettes Later chapters desc n b e the modification of these methods for single cardiac cells and egg cells, provide a primer on the isolation of nerve cells from molluscs and from vertebrate dorsal root ganglia, and give advice on the considerations that govern the building of voltage clamp circuits In detail, the design is faulted by a certain v a n a b i h t y in quality of the chapters, though several are very good. T h e r e is also an elem e n t of repetition, for example, three chapters begin with much the same history of the method Many typographical errors remain, particularly in scientific umts Despite all this, the book remains very readable and will, I think, be useful Most chapters contain sufficient instructions on setting up the methods to get their readers most of the way there without too much trouble Particularly useful in this regard are the chapters. describing the use of glass pipettes (which deals with general principles), the construction of the plastic pipettes used in Kostyuk's laboratory, and the method of perfusing egg cells These
chapters also contain clear advice on elecmcal matters. The problem of washout of enzyme systems is dealt with less fully than its importance may warrant for someone wanting to investigate intracellular modulation of channel function_ I should have liked to have seen a brief discussion of the relative merits of other methods, such as the introduction of substances into intact cells by pressure InJection or after brief exposure of cells to electnc shocks (tantalizingly briefly described in the first chapter), the use of excised m e m b r a n e patches, and channel remcorporatlon as approaches to problems associated with second messengers, P F. Baker's chapter, in considenng the design of internal solutions, deals most fully with this Issue A b s e n t is any account of the use of cut m y e h n a t e d nerve or muscle fibres in so-called vasehne or sucrose gap methods Yet the internal solution can be altered by these means. These gap methods only appear in the chapter on cardiac cells, where familiar arguments condemn their use with multicellular preparations. The chapter on isolation of nerve cells contains useful, though b n e f advice That on the design of circuits is too mathematical for my taste, with the practical advice not always easily extracted. In spite of these criticisms, the book will be useful to anyone wanting to set up the m e t h o d for the first time It contains the necessary reopes, coupled with practical hints for making things work
of
edited by P_ G. Kostyuk and O. A. Krtshtal, John Wiley and Sons, 1984 £10.00 (xi: + 133 pages) ISBN 0 471 90392 2 (soft cover) Over the past decade or so a variety of new electrophysiologmal techniques have become available, with two welcome consequences. First, it has spread electrophysiologacal ideas to the study of cell types not classically regarded as electrically excatable Secondly, these methods have permitted and helped encourage an increasing co-operation between biochemists and o t h e r cell biologists seeking to understand how m e m b r a n e ionic channels control cellular functmn and how they are m turn controlled. I m p o r t a n t , though not supreme, among these techniques is that of intracellular perfusion or dialysis, where m e a s u r e m e n t of iomc movements is coupled with control of the ionic and o t h e r contents of the cell. Given that the m e t h o d has developed from perfusmn of the squid giant axon, first c a m e d out around 1960, it has already contributed to knowledge of the properties of ionic channels and of the mechanisms of active transport and facalitated transfer. For the present and future, perfuslon also offers one way of investigating how memb r a n e function is controlled through mtracellular messengers such as cyclic nucleotades and metabolites of inositol phospholipids. Since the m e t h o d can now be applied to m a m m a h a n nerve cells and since many neuroscientists are interested m the way intracellular
R P FUTRELLE
Department of Geneac~ and Development, the Untverszty of lllmots at Urbana-Champatgn, Urbana, IL 61801, USA
P R STANFIELD
Department of Physiology, Umverslty of Leicester, Leicester LE 7RH, UK