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Disorders of the motor unit
500
Book reviews
Disorders of the Motor Unit. Edited by DONALD L. SHORTLAND. Published by J. Wiley & Sons, 1982. ISBN 0-471-09507-9.
Insect Neurohormones. MARIk RAABI. Published by Plenum Press, 1982. Price $42.50. ISBN 0-306-40782-5.
The book is the outcome of a meeting organised by the Muscular Dystrophy, Association (M.D.A.) of America in Miami in 1980. The title is possibly misleading as it suggests that there is no discussion of events occurring below the level of the cell membrane. Happily, this is not the case and the first article by Dr H. E. Huxley sets the scene as to how modern concepts of force development in skeletal muscle have developed from the use of X-ray diffraction methods. He brings his ideas up to date with the most recent work using time-resolved X-ray diffraction methods in order to follow rapid changes in myosin cross-bridge movement. The main body of papers by individual workers and their collaborators cover a wide scope of interests: peripheral nerve disorders, cell cell interactions, myasthenia gravis, biochemical and morphological aspects of membranes and muscular dystrophy, muscle and calcium, alterations in metabolic regulation, genetic control of protein synthesis, aspects of carrier detection, and muscles in culture. It would be an invidious task for a reviewer to single out by name any of the contributions for special mention. However, work using fluorescence labelled monoclonal antibodies to label specific muscle membrane and secretory proteins, allows the investigator in theory the same degree of specificity as :~BTx has for the acetylcholine receptor. Although the work is still in its early stages the results obtained so far indicate the potential strength of the method. The section on the nature of excitable channels in the sarcolemma and T-tubule system gives a good picture of the current ideas on the nature of the channels and their specificity. Also described are the current methods and progress made in is~olating these components. This work combined with recent ideas on mechanisms of axonal transport, likely to be controlled by phosphorylation processes as well as by free Ca 2 +, made fascinating reading. As might have been expected there was an extensive section on changes in calcium metabolism particularly aimed at possible changes in the activity of the calcium p u m p of the sarcoplasmic reticulum. The nuclear magnetic resonance (NMR) studies on intact muscle, a relatively new method, gives a valuable insight into the phosphorous metabolism of a muscle cell by a non-invasive method. Virtually each chapter has a record of the discussion following each talk, which gives a feeling of the meeting and conveys to the reader the reception of the papers and the excitement generated. This, 1 feel, adds to the book's interest, otherwise it might simply become yet another record of a symposium. It is, however, fortunately much more than that, well produced and edited by Dr Donald Schotland, and can be recommended to any library and research group having interests in this wide-ranging area.
Since the pioneering work of the Scharrers there has been a vast volume of research on neurosecretion in insects and it is opportune that a volume devoted to a review of the literature on insect neurohormones should be published. Both the author, Marie Raabe and the translator, Nissim Marshall are to be congratulated, as is the illustrator, Daisy Chervin, for the quality of the text and diagrams. As is abundantly clear from the first chapter in this book, there have been many neurosecretory factors proposed, using histochemical techniques, in a wide range of insect species. It is equally clear that there is a great range in the neurohaemal systems of insects which can at times make comparison difficult. Dr. Raabe draws a conclusion at the end of the first chapter which 1 fully concur with, namely that a clear distraction between neurohormones and neurotransmitters can no longer be made. Some neurohormones are released directly onto the effector organ while some amines are released into thc circulation and have their action at some distance from their point of release. This finding is becoming clear from work on many diverse groups of animals. A limiting factor in tile identification of hormones is thc lack of chemical identification and this wilt prove a very important area for future research in this subject. It is necessary for a close collaboration between those interested in the identification of insect neurohormones and synthetic chemists. It will also mean an increasing use of the recently developed biochemical techniques for the analysis of small a m o u n t s of naturally occurring material. The second chapter reviews thc control of endocrine activity and concludes that the corpora allata is under both excitatory and inhibitory control from the brain. It is clear that a number of neurohormones are active on insect visceral muscle. One of these factors has been identified and sequenced, proctolin, thanks to the pioneering work of Brown. Recently using immnnocytochemical techniqncs, proctolin has been localised m specific neurones in the insect central nervous system and its peripheral actions analysed. The type of work currently in progress with proctolin indicates the way in which the identity, localisation and site of action of many other peptide neurohormones should be investigated. A chapter is devoted to the role of neurohormones m the regulation of colour change in insects and it is apparent that they play a leading role in both morphological and physiological colour change. N e u r o h o r m o n e s PlaY an important role in behavioural and rhythmic activities, e.g, migration, eclosion, prepupal retraction and circadian rhythms. The control of water metabolism is also under neurhormonal control and is probable that all insects possess a diuretic hormone but little is known concerning the stimuli that control its release. The actual releasi~ sites are probably the corpora cardiaca and perisympathqtic organs. Recently an ion regulating hormone has also been postulated, distinct from a diuretic factor. A t t e m p t s have been made to purify these factors and their approximate molecular weights have been determined. The step is the identification of their amino acid sequences. Insect metabolic processes are reviewed m detail prior to an analysis of the role of neurohormones in their regu-
CHRIS C. ASHLEY
Chris Ashley is at the University Laboratory ol Physiology, University of Oxlbrd, Oxford OX 1 3PT, U.K.
Book reviews
Disorders of the Motor Unit. Edited by DONALD L. SHORTLAND. Published by J. Wiley & Sons, 1982. ISBN 0-471-09507-9.
Insect Neurohormones. MARIk RAABI. Published by Plenum Press, 1982. Price $42.50. ISBN 0-306-40782-5.
The book is the outcome of a meeting organised by the Muscular Dystrophy, Association (M.D.A.) of America in Miami in 1980. The title is possibly misleading as it suggests that there is no discussion of events occurring below the level of the cell membrane. Happily, this is not the case and the first article by Dr H. E. Huxley sets the scene as to how modern concepts of force development in skeletal muscle have developed from the use of X-ray diffraction methods. He brings his ideas up to date with the most recent work using time-resolved X-ray diffraction methods in order to follow rapid changes in myosin cross-bridge movement. The main body of papers by individual workers and their collaborators cover a wide scope of interests: peripheral nerve disorders, cell cell interactions, myasthenia gravis, biochemical and morphological aspects of membranes and muscular dystrophy, muscle and calcium, alterations in metabolic regulation, genetic control of protein synthesis, aspects of carrier detection, and muscles in culture. It would be an invidious task for a reviewer to single out by name any of the contributions for special mention. However, work using fluorescence labelled monoclonal antibodies to label specific muscle membrane and secretory proteins, allows the investigator in theory the same degree of specificity as :~BTx has for the acetylcholine receptor. Although the work is still in its early stages the results obtained so far indicate the potential strength of the method. The section on the nature of excitable channels in the sarcolemma and T-tubule system gives a good picture of the current ideas on the nature of the channels and their specificity. Also described are the current methods and progress made in is~olating these components. This work combined with recent ideas on mechanisms of axonal transport, likely to be controlled by phosphorylation processes as well as by free Ca 2 +, made fascinating reading. As might have been expected there was an extensive section on changes in calcium metabolism particularly aimed at possible changes in the activity of the calcium p u m p of the sarcoplasmic reticulum. The nuclear magnetic resonance (NMR) studies on intact muscle, a relatively new method, gives a valuable insight into the phosphorous metabolism of a muscle cell by a non-invasive method. Virtually each chapter has a record of the discussion following each talk, which gives a feeling of the meeting and conveys to the reader the reception of the papers and the excitement generated. This, 1 feel, adds to the book's interest, otherwise it might simply become yet another record of a symposium. It is, however, fortunately much more than that, well produced and edited by Dr Donald Schotland, and can be recommended to any library and research group having interests in this wide-ranging area.
Since the pioneering work of the Scharrers there has been a vast volume of research on neurosecretion in insects and it is opportune that a volume devoted to a review of the literature on insect neurohormones should be published. Both the author, Marie Raabe and the translator, Nissim Marshall are to be congratulated, as is the illustrator, Daisy Chervin, for the quality of the text and diagrams. As is abundantly clear from the first chapter in this book, there have been many neurosecretory factors proposed, using histochemical techniques, in a wide range of insect species. It is equally clear that there is a great range in the neurohaemal systems of insects which can at times make comparison difficult. Dr. Raabe draws a conclusion at the end of the first chapter which 1 fully concur with, namely that a clear distraction between neurohormones and neurotransmitters can no longer be made. Some neurohormones are released directly onto the effector organ while some amines are released into thc circulation and have their action at some distance from their point of release. This finding is becoming clear from work on many diverse groups of animals. A limiting factor in tile identification of hormones is thc lack of chemical identification and this wilt prove a very important area for future research in this subject. It is necessary for a close collaboration between those interested in the identification of insect neurohormones and synthetic chemists. It will also mean an increasing use of the recently developed biochemical techniques for the analysis of small a m o u n t s of naturally occurring material. The second chapter reviews thc control of endocrine activity and concludes that the corpora allata is under both excitatory and inhibitory control from the brain. It is clear that a number of neurohormones are active on insect visceral muscle. One of these factors has been identified and sequenced, proctolin, thanks to the pioneering work of Brown. Recently using immnnocytochemical techniqncs, proctolin has been localised m specific neurones in the insect central nervous system and its peripheral actions analysed. The type of work currently in progress with proctolin indicates the way in which the identity, localisation and site of action of many other peptide neurohormones should be investigated. A chapter is devoted to the role of neurohormones m the regulation of colour change in insects and it is apparent that they play a leading role in both morphological and physiological colour change. N e u r o h o r m o n e s PlaY an important role in behavioural and rhythmic activities, e.g, migration, eclosion, prepupal retraction and circadian rhythms. The control of water metabolism is also under neurhormonal control and is probable that all insects possess a diuretic hormone but little is known concerning the stimuli that control its release. The actual releasi~ sites are probably the corpora cardiaca and perisympathqtic organs. Recently an ion regulating hormone has also been postulated, distinct from a diuretic factor. A t t e m p t s have been made to purify these factors and their approximate molecular weights have been determined. The step is the identification of their amino acid sequences. Insect metabolic processes are reviewed m detail prior to an analysis of the role of neurohormones in their regu-
CHRIS C. ASHLEY
Chris Ashley is at the University Laboratory ol Physiology, University of Oxlbrd, Oxford OX 1 3PT, U.K.