1987 |
Bookman, Richard John |
F32Activity Code Description: To provide postdoctoral research training to individuals to broaden their scientific background and extend their potential for research in specified health-related areas. |
Calcium and Transmitter Release |
0.972 |
1990 — 1994 |
Bookman, Richard |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Measurements of Excitation-Secretion Coupling in Single Cells @ University of Miami School of Medicine
Neurotransmitters and neurohormones are released from a neuron or endocrine cell primarily through the process of exocytosis. Central to this process is the calcium-dependent fusion of a small, membrane-limited vesicle with the outer membrane of the cell. Two immediate consequences of this fusion are the release of the vesicle contents (transmitter or hormone) into the extra- cellular space and an increase in the surface area of the cell. This project will provide basic information about the mechanism of transmitter release by exploiting recent technical advances to measure these minute changes in cell surface area. Using the adrenal chromaffin cell as a model system and triggering release by brief changes in the electrical potential across the cell membrane, this project will provide new information about the quantitative relationship between calcium and transmitter release.
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0.915 |
1994 — 1997 |
Bookman, Richard |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Instrumentation For High Resolution Capacitance Measurements @ University of Miami School of Medicine
9318259 Bookman Support from the NSF is requested for the development of new instrumentation to measure rapid changes in the capacitance of biological membranes with high resolution. These measurements of changes in capacitance will permit the investigation of a number of biologically important phenomena. The principal use of this instrument is likely to be the detection of increases in cell surface area arising from the fusion of one or more secretory vesicles with the cell's plasma membrane during the process of exocytosis. The study of secretory vesicle fusion events and the quantitative characterization of the kinetics of secretion made possible by this instrument can improve our understanding of a fundamental process in cell biology. An additional component of membrane capacitance arises from the mobility of charged groups on proteins lying within the electric field of the membrane. Recent results show that the detection of such charge movements from voltage-dependent ion channels as a capacitance signal can provide new information about ion channel gating and its modification by toxins. Thus it is expected that the proposed instrument can help to establish new methods for studying conformational changes of membrane proteins. The project consists of the development of software to implement a stimulus synthesizer, the development of improved and user-tunable algorithms for measuring membrane capacitance, their implementation in software, development of new analysis and data base tools for the data produced by this instrument, and documentation of the instrument for both users and programmers. The fundamental assumptions behind this instrument include: 1) that the cell under study can be represented by an equivalent electrical circuit, and 2) that a cell under voltage clamp can be driven by a band-limited, arbitrary-frequency voltage stimulus and the resulting current can be faithfully sampled with high resolution. Based on these assumptions, the inst rument will be able to combine traditional transient membrane depolarization with more spectrally complicated waveforms in order to study processes activated by the cell's electrical activity. This proposed instrument will attempt to resolve changes in membrane capacitance that are on the order of 10-1s Farads and to resolve such changes occurring in a 1kHz bandwidth. This instrument is an example of a new class of instrumentation made possible by developments in three areas of technology: 1) high speed general purpose microprocessors, 2) fast, high resolution A/D and D/A converters, and 3) special purpose digital signal processing algorithms. A key feature of this project is the reliance upon hardware components that already exist in most laboratories, i.e., a personal computer and a data acquisition interface. With the increasing power of the scientist's data acquisition computer, new types of measurements become possible solely by the addition of software. With its implementation of appropriate algorithms, the proposed instrument will provide information that is unattainable with any commercial instrument and make possible new types of experiments to study membrane processes. A particular advantage is that the proposed instrument can be widely and rapidly disseminated to the research community electronically (i.e., through Internet)) at no additional capital cost to the nation's laboratories.
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0.915 |
1997 — 2004 |
Bookman, Richard John |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Cellular Basis of Airway Secretion Clearance Coupling @ University of Miami School of Medicine
Tracheal epithelial cells play a vital role in pulmonary host defense by clearing foreign materials from the airways through the process of mucociliary clearance. Despite this critical role, our understanding of the cellular and molecular mechanisms responsible for the regulation of mucociliary clearance is far from complete. The broad, long-term hypothesis of this project is that effective clearance depends on cooperative actions and coordinated responses of ciliated cells and mucus-secreting cells. We refer to this as 'secretion-clearance coupling'. Parasympathetic cholinergic input to the airway, acting via muscarinic receptors, plays an important role in regulating mucociliary clearance and these receptors are found on both ciliated cells and submucosal glands. In this proposal, we seek to understand the mechanisms responsible for the regulation of ciliary beating frequency (CBF) by acetylcholine (ACh). We hypothesize that ACh, acting through m3 muscarinic receptors on ciliated cells, has dual, opposing actions on CBF and, further, that these actions are mediated by changes in cytoplasmic free Ca2+ concentration [Ca2+]i resulting from ACh activation of this G-protein coupled receptor. The net result of these opposing actions serves to give the ciliated cell an extraordinary degree of fine control in regulating CBF responses. In order to test this hypothesis, we will examine, using high resolution digital video microscopy, mechanisms by which ACh can raise and lower [Ca2+]i, measure the tightness of coupling between Ca2+ and CBF, and begin to identify signaling molecules that mediate such coupling. The specific aims are: I) To define the mechanisms responsible for regulating [Ca2+]i in ciliated cells in response to ACh. II) To characterize the kinetics of coupling between [Ca2+]i and CBF. Ill) To characterize the molecular site of Ca2+ action. An increased understanding of the normal mechanisms that regulate ciliary beating will help to define the basis for defective mucociliary clearance in such common diseases as asthma and chronic bronchitis. Present day therapy for mucociliary dysfunction is unsatisfactory. The proposed experiments will help to identify molecular targets that might serve as the basis for novel treatment strategies for such airway diseases.
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