Miriam Salpeter - US grants

The proposed research will explore new approaches to the application of quantitative electron microscope (EM) autoradiography for studies in cell biology. These new approaches will include: tract autoradiography for use with high energy isotopes; EM autoradiography with the scanning electron microscope; and test specimens for soluble compound autoradiography. As new procedures are developed, they will be applied to specifc cell biology problems dealing with: cell surface molecules such as receptors, ion channels and pumps; internalization of membrane components; and intracellular pathways for transport and secretion.

DESCRIPTION: (Applicant's Abstract) The long term objectives of this proposal are to develop high resolution autoradiographic procedures, especially for use with the scanning electron microscope (ScEM). These are then to be applied together with other cellular and molecular techniques, to the study of specific problems in neurocytology. The proposed technical advances involve: the use of reversible (soluble) probes for labeling molecules for which no irreversible probes are yet available, calibrating the sensitivity and resolution of the technique, and devising methods for analyzing autoradiograms from thick specimen after in situ hybridization. The surface molecules to be studied are the voltage sensitive sodium channels on muscle and nerve cells, and the nicotinic acetylcholine receptors (AChRs) both on myotubes in culture, and on neurons; ScEM autoradiography will also be applied to analyze the perinuclear distributions of AChR and ACh esterase (AChE) transcripts in muscle during development and at the adult neuromuscular junction. Since the interactions between cells of the nervous system underlie a wide variety of mental, emotional and behavioral processes, information on the quantitative distribution of the molecules involved in those interactions should provide a wider understanding of the mechanisms involved.

Schneiderman 9422143 During the development of the neuromuscular system, a series of complex interactions are involved in the specification of the pattern of innervation of any specific muscle. This research is designed to elucidate the sequence of events that result in the development of the appropriate connections between neurons and muscles. To address this problem a novel invertebrate system will be employed. The innervation of muscles will be studied during the process of metamorphosis, when degenerating muscles are being replaced with newly formed muscles. In particular, the role of hypothesized "muscle pioneer cells" in neural specification will be examined. The results of this research will provide basic information about the major steps involved in the development of connections between neurons and muscles, as well as insight into the plasticity inherent in the developing and regenerating neuromuscular system.

technology /technique development; proteins; nervous system; enzymes; computers; biomedical resource; biological products;