RUI: Role of Peptides in Modulating the Output of a Small Neural System

点击翻译按钮获取中文摘要

In recent years, an enormous number of neurotransmitter and neuromodulatory substances have been identified in both vertebrate and invertebrate substances. These substances include a number of amines and an ever-increasing number of neuropeptides, the exact physiological roles of which are still unclear. However, it appears in many cases that the peptides are modulatory in nature, provoking relatively long-term alterations of ongoing neuronal activity or inducing such activity in previously quiescent preparations. Such modification and modulation of neuronal activity is common to all animals, and is essential to a wide variety of activities. Studies of the roles of neuropeptides in modulating neuronal activities will thus serve to clarify further not only the physiological roles of the many substances found in the nervous system but also the mechanisms by which neuronal modulation can occur. Perhaps the most amenable systems for the study of modulation at present are those systems in which a regularly patterned activity occurs. One such system, in which the role of peptides in modulating neuronal activity can be addressed readily, is the stomatogastric nervous system of decapod crustaceans. Questions related to the peptidergic modulation of neuronal activity, particulary rhythmically patterned activity, have already been approached from several perspectives. Considerable effort has been devoted to identifying and localizing a variety of neuropeptides in the stomatogastric system. In addition, the physiological effects of a number of neuropeptides on the stomatogastric system have been studied. Furthermore, at least one modulatory neuron has been identified, and its modulatory effects on the system have been studied. What is lacking, however, is the synthesis of these three types of experiments, the positive identification of the transmitters used by individual modulatory neurons and the effects of these neurons when fired in a physiologically relevant manner. The present study by Dr. Patsy Dickinson is designed to begin to fill this gap in our knowledge in two ways: (1) by identifying and recording from neurons containing neuropeptides, and (2) by examining modulatory neurons for the presence of these neuropeptides.