Preface

Abstract

The discovery of nerve growth factor (NGF) some four decades ago allowed new types of question to be asked about the nervous system. The same discovery, and subsequent ones, have also slowly revealed answers to some of those questions. Interest in the role of trophic factors in the development and maintenance of the nervous system has persisted unabated for four decades. Indeed it has steadily grown over this period. The impact of this field of study is reflected in the award of the Nobel prize for Medicine to Dr Levi-Montalcini and Dr Cohen for their work on NGF. For 20 or 30 years after its discovery, the effects of NGF (and subsequently other neurotrophic factors) were of interest mainly to developmental neurobiologists. The principal tools available during this period were the protein itself and antibodies to it. These were used imaginatively in a wide variety of in vivo and in vitro studies. With only limited knowledge it was possible to make progress on important general questions. For instance, binding studies of labelled NGF revealed much about the nature and distribution of receptors long before they were identified.