1985 — 1993 |
Kitai, Stephen T |
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. |
Experimental Studies of Sensory Pathways @ University of Tennessee Health Sci Ctr
An important feature of the proposed work is its aim to extend the high resolution of single neuron analysis with combined anatomical and histochemical techniques in a direction that will enable more precise description of cytoarchitechtonics of neuronal elements in the basal ganglia and at the same time enable more meaningful interpretation of various nuclear functions of the basal ganglia that can be obtained by conventional single or multiple unit recording or by conventional anatomical technique. The problems of interest will be addressed with intensive usage of the well established methodology in our laboratory whereby intracellular recording and intracellular labeling with horseradish peroxidase are combined with subsequent light and electron microscopic analysis. In addition, histochemical methods including retrograde and anterograde transport techniques and conventional anatomical techniques such and Golgi and Nissl methods will be employed. Immunocytochemical techniques with capability of analysis at light and electron microscopic level and the in vitro slice preparation, pharmacological and ionic manipulations (i.e. microelectrophoresis of transmitter substances and/or substitution of cellular ionic components) will also be incorporated in this convergent multidisciplinary analysis. This methodology will be directed, in species to include rats, cats and monkeys, to the following questions: (1) The intrinsic organization of the striatum (description of morphological substrates for and functional interactions between neuronal elements within the striatum), (2) The extrinsic inputs to the striatum (A further analysis of the nigral, thalamic and cortical inputs), (3) The striatal projection system (Morphological and physiological identification of striatal projection neurons, the course and termination of their axons, and their target neurons), (4) Morphological and physiological identification of pallidal neurons and (5) Morphological and physiological identification of the subthalamic neurons. Disequilibria of cholinergic, dopaminergic, and GABA-ergic systems in the basal ganglia are suspected to be involved in the pathophysiology of basal ganglia disease. The search for more specific treatments will be facilitated my more clear understanding of specific nature of the basal ganglia components and subsequent imbalance of extra-pyramidal operation.
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0.988 |
1986 — 1989 |
Kitai, Stephen T |
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. |
Anatomy and Physiology of the Basal Ganglia @ University of Tennessee Health Sci Ctr
The aim is to obtain more precise description of internuclear relationship among the subthalamus (STh), the substantia nigra (SN), and the globus pallidus (GP). The problems of interest will be addressed with intensive usage of the well established methodology in our laboratory whereby intracellular recordings and labeling with HRP and neuropharmacological analysis in an in vitro preparation, light and electronmicroscopic analysis of the structures labeled by axonally transported PHA-L lectin and localized by immunohistochemical method. Intracellular recordings are intended to reveal synaptic actions, cell firing patterns and membrane characteristics, neuropharmacological analysis to reveal actions of putative transmitters suspected to operate in these circuits, PHA-L immunohistochemistry to reveal morphological features, at both light and ultrastructural level, of the subthalamic, pallidal and nigral axonal terminals and terminal plexus. The convergent multidisciplinary analysis of physiology, pharmacology and anatomy will be directed, in rats, to the following questions: (1) What are the membrane characteristics of STh, SNr and GP neurons? (2) What is the mode of action of STh inputs to SN and GP, and the suspected putative transmitters? (3) What is the mode of action of GP inputs to STh and the putative neurotransmitters? (4) What is the mode of action of SN inputs to STh and its putative neurotransmitters? (5) What are the morphological features of STh axon terminals in SN and GP, GP and SN terminals in STh? Disequilibria of cholinergic, dopaminergic and GABAergic systems in the basal ganglia are suspected to be involved in the pathophysiology of basal ganglia disease. The research for more specific treatments will be facilitated by clear understandings of specific functional nature of the basal ganglia components (e.g., STh, SN, GP) in terms of physiology, pharmacology and anatomy.
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0.988 |
1988 — 2001 |
Kitai, Stephen T |
P01Activity Code Description: For the support of a broadly based, multidisciplinary, often long-term research program which has a specific major objective or a basic theme. A program project generally involves the organized efforts of relatively large groups, members of which are conducting research projects designed to elucidate the various aspects or components of this objective. Each research project is usually under the leadership of an established investigator. The grant can provide support for certain basic resources used by these groups in the program, including clinical components, the sharing of which facilitates the total research effort. A program project is directed toward a range of problems having a central research focus, in contrast to the usually narrower thrust of the traditional research project. Each project supported through this mechanism should contribute or be directly related to the common theme of the total research effort. These scientifically meritorious projects should demonstrate an essential element of unity and interdependence, i.e., a system of research activities and projects directed toward a well-defined research program goal. U19Activity Code Description: To support a research program of multiple projects directed toward a specific major objective, basic theme or program goal, requiring a broadly based, multidisciplinary and often long-term approach. A cooperative agreement research program generally involves the organized efforts of large groups, members of which are conducting research projects designed to elucidate the various aspects of a specific objective. Substantial Federal programmatic staff involvement is intended to assist investigators during performance of the research activities, as defined in the terms and conditions of award. The investigators have primary authorities and responsibilities to define research objectives and approaches, and to plan, conduct, analyze, and publish results, interpretations and conclusions of their studies. Each research project is usually under the leadership of an established investigator in an area representing his/her special interest and competencies. Each project supported through this mechanism should contribute to or be directly related to the common theme of the total research effort. The award can provide support for certain basic shared resources, including clinical components, which facilitate the total research effort. These scientifically meritorious projects should demonstrate an essential element of unity and interdependence. |
Morphology and Function of the Basal Ganglia @ University of Tennessee Health Sci Ctr
The goal of this program is to investigate the function and development of the basal ganglia using a variety of techniques and preparations. The strength of the proposal has been built from established work in each of six laboratories, whose principal investigators possess diverse backgrounds representing the fields of anatomy, electrophysiology, pharmacology, molecular and cell biology, and behavior. These investigators are united by a common cause; namely to understand the function and development of the basal ganglia under a multidisciplinary and highly interactive research program. We plan to investigate a) development of synapses and order and topography in the neostriatum, b) development of transmitter and morphological phenotype of the striatal neurons and the characterization of their ionic conductances, c) action of putative transmitters on the basal ganglia neurons, d) identification of new putative neurotransmitters in the globus pallidum, e) single-unit activities in the basal ganglia of awake animals, and f) brain graft in the basal ganglia. Project 1 will intend to characterize in the primary dissociated rat explant culture the expression of neurotransmitter and morphological phenotypes using immunocytochemical techniques in conjunction with light and electronmicroscopy, ionic conductances by whole-cell and single-channel voltage clamp techniques, and electrophysiological effects of dopamine on these neurons. Project 2 will examine the action of dopamine and acetylcholine in in vivo rats striatal slice preparation by the intracellular recording technique and morphological relationship between dopamine afferents and striatal neurons. Project 3 study the firing pattern of striatal neurons during the performance of a sensory-triggered movement tasks in the primate. Concomitant anatomical studies, using immunocytochemical tracing combined with light and electronmicroscope are proposed. Project 4 will determine the extent to which the normal cellular connectional arrangements are reproduced in striatal graft by intracellular recording and PHA-L tracing methods in conjunction with light and electron microscopy.
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0.988 |
1990 — 1994 |
Kitai, Stephen T |
T32Activity Code Description: To enable institutions to make National Research Service Awards to individuals selected by them for predoctoral and postdoctoral research training in specified shortage areas. |
Predoctoral and Postdoctoral Training in Neuroscience @ University of Tennessee Health Sci Ctr |
0.988 |
1994 |
Kitai, Stephen T |
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. |
Sensory Pathways @ University of Tennessee Health Sci Ctr
The proposed work aims to extend the high resolution of single neuron analysis with combined anatomical and immunocytochemical techniques for a more precise description of cellular, electrical membrane and ionic currents; neurotransmitter and neuromodulator action; and circuits of neuronal elements in the basal ganglia. Moreover, at the same time, the proposed work aims to provide a more meaningful interpretation of various nuclear functions of the basal ganglia than can be obtained by conventional single or multiple unit recording or by conventional anatomical technique. The areas of interest will be addressed with intensive usage of the well established methodology in our laboratory, whereby, intracellular recording and intracellular labeling with biocytin and other labeling materials are combined with subsequent light and electron microscopic analysis. In addition, histochemical methods, including retrograde and anterograde transport techniques, will be employed. This convergent multidisciplinary analysis will be directed to in vitro slice preparation and cultured and acutely dissociated neuron preparation obtained from rat neostriatum globus pallidus, entopeduncular nucleus, substantia nigra, and subthalamus to three sets of aims: The first set will characterize the membrane properties (including ionic conductances such as K, Na, Ca, etc.) of the neuron by the use of whole-cell (voltage) clamp technique in acutely dissociated or cultured neurons or by an intracellular current clamp recording in slice preparation. The second set will delineate the action of putative neurotransmitters or neuromodulators by monitoring changes in ionic conductances produced by the drugs or their agonists and antagonists. The transmitters to be studied are dopamine (DA), glutamate, and acetylcholine (ACh), which are the major known neurotransmitters and modulators involved in these nuclear operation. We will identify the transmitter and morphological phenotypes of the neurons under study by anatomical techniques by combined techniques of immunocytochemistry. The third set is to re-examine functional circuits involved among these nuclei (e.g., subthalamo-pallidal, striato-nigral, etc.) by trigger-averaging techniques with simultaneous recordings from the projection and its target neurons. Disequilibria of cholinergic, dopaminergic, glutaminergic, and GABAergic systems in the basal ganglia are believed involved in the pathophysiology of basal ganglia disease. The search for more specific treatments will be facilitated by a clearer understanding of the specific nature of the basal ganglia anatomy, physiology, pharmacology, and subsequent imbalance of extra-pyramidal operation.
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0.988 |
1995 — 2001 |
Kitai, Stephen T |
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. |
Experimental Studies in Sensory Pathways @ University of Tennessee Health Sci Ctr
Normal basal ganglia function is highly dependent on the activities of dopaminergic (DA) neurons in the SNc and GABAergic neurons in SNr/EP. However, many aspects of the mechanisms controlling SNc and SNr neural activity which influence dopamine and GABA release at their projection targets are still not well understood. Recently there has been a growing interest in converging inputs from the tegmental pedunculopontine (PPN) and subthalamic nucleus (STN) to the SNc DA and SNr GABA neurons. Although the functional role of these inputs is poorly understood, our previous studies suggested that acetylcholine (ACh) inputs from PPN depolarize the resting membrane potential of DA and GABA neurons by a combination of increased cationic influx and decreased K+ efflux, and reduces Ca2+ entry during the pacemaker-like slow depolarization (PLSD), which decreases the amplitude and duration of the subsequent spike after hyperpolarization. We, therefore, hypothesize that (1) the action of ACh increases the tendency for SNc DA and SNr GABAergic neurons to exhibit burst firing in response to glutamatergic (glu) input from the STN and PPN and (2) in addition to glu and ACh excitatory projections from the PPN and STN, but also GABAergic inhibitory projections to SN (causing disinhibition of GABA system by phasic inhibition of the SNr neurons) are modulating SNc DA and SNr GABAergic neuronal firing behavior. To test these hypothesis, we will utilize the newly developed in vitro organotypic culture preparation consisting of PPN, SN, STH and STR to conduct morphological and electrophysiological studies. Morphological studies will involve light and electron microscopy to (1) identify ACh, glu and GABAergic projection patterns and their terminal sites on the SNc DA and SNr GABA neurons, (2a) identify the nuclear origin of ACh and glu projections to SNc DA and SNr GABAergic neurons with a combined biocytin intracellular labeling, and (2b) identify the locations of the intracellularly labeled biocytin terminals making synapses with SNc DA and SNr GABA neurons and (3) identify the location of ACh, glu and GABA receptors on the SNc DA and SNr GABA neurons. Electrophysiological studies will involve use of whole-cell (current) clamp or intracellular sharp electrode recording to delineate the effect of (1) cholinergic receptor activation on Ca2+ entry during the PLSD and AHP,(2) the effect of excitatory synaptic inputs from PPN and STN and GABAergic inhibitory inputs from the STR on firing properties and bursting of SNc DA and SNr GABAergic neurons. Understanding the role of multiple inputs in the control and/or modulation of SNc and SNr cellular activity which affect their target structures (i.e. striatum and thalamus) is of fundamental importance relative to motor and behavioral function as well as clinical entities such as Parkinson's disease.
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0.988 |
1996 — 2002 |
Kitai, Stephen T |
P01Activity Code Description: For the support of a broadly based, multidisciplinary, often long-term research program which has a specific major objective or a basic theme. A program project generally involves the organized efforts of relatively large groups, members of which are conducting research projects designed to elucidate the various aspects or components of this objective. Each research project is usually under the leadership of an established investigator. The grant can provide support for certain basic resources used by these groups in the program, including clinical components, the sharing of which facilitates the total research effort. A program project is directed toward a range of problems having a central research focus, in contrast to the usually narrower thrust of the traditional research project. Each project supported through this mechanism should contribute or be directly related to the common theme of the total research effort. These scientifically meritorious projects should demonstrate an essential element of unity and interdependence, i.e., a system of research activities and projects directed toward a well-defined research program goal. U19Activity Code Description: To support a research program of multiple projects directed toward a specific major objective, basic theme or program goal, requiring a broadly based, multidisciplinary and often long-term approach. A cooperative agreement research program generally involves the organized efforts of large groups, members of which are conducting research projects designed to elucidate the various aspects of a specific objective. Substantial Federal programmatic staff involvement is intended to assist investigators during performance of the research activities, as defined in the terms and conditions of award. The investigators have primary authorities and responsibilities to define research objectives and approaches, and to plan, conduct, analyze, and publish results, interpretations and conclusions of their studies. Each research project is usually under the leadership of an established investigator in an area representing his/her special interest and competencies. Each project supported through this mechanism should contribute to or be directly related to the common theme of the total research effort. The award can provide support for certain basic shared resources, including clinical components, which facilitate the total research effort. These scientifically meritorious projects should demonstrate an essential element of unity and interdependence. |
Core--Central Facilities @ University of Tennessee Health Sci Ctr |
0.988 |
1998 — 2002 |
Kitai, Stephen T |
P01Activity Code Description: For the support of a broadly based, multidisciplinary, often long-term research program which has a specific major objective or a basic theme. A program project generally involves the organized efforts of relatively large groups, members of which are conducting research projects designed to elucidate the various aspects or components of this objective. Each research project is usually under the leadership of an established investigator. The grant can provide support for certain basic resources used by these groups in the program, including clinical components, the sharing of which facilitates the total research effort. A program project is directed toward a range of problems having a central research focus, in contrast to the usually narrower thrust of the traditional research project. Each project supported through this mechanism should contribute or be directly related to the common theme of the total research effort. These scientifically meritorious projects should demonstrate an essential element of unity and interdependence, i.e., a system of research activities and projects directed toward a well-defined research program goal. |
Rhythmicity and Synchrony in the Pallido/Subthalamic Recurrent Feedback Loop @ University of Tennessee Health Sci Ctr
Parkinson's disease (PD), typified by motor dysfunction, is one of the most common neurodegenerative disorders and arises from a degeneration of dopaminergic cells which project to the striatum (Str). In the MPTP model for PD, recordings from the awake monkey have demonstrated that this type of tremor is correlated with rhythmic synchronized burst activity (RSBA) in the subthalamic (STN) and the globus pallidus (GP). Our primary hypothesis is that a recurrent feedback loop between the STN and the GP generates the RSBA in the absence of dopamine. In order to test this hypothesis, we will examine four major points. First, what are the morphological and electrophysiological properties of intrinsically bursting GP and STN cells? Second, is the GP necessary for the generation of RSBA? Third, what is the function of voltage-gated calcium channels and GABAa receptors in the generation of RSBA? Fourth, do dopaminergic inputs affect the generation of RSBA in the STN-GP circuitry? We will employ four different methodological approaches to answer these questions. First, in electrophysiologically and morphologically characterized neurons from GP and STN, we will study the RSBA within and between the STN and the GP using simultaneous intra- and extracellular recording. Second, the contribution of the GP to RSBA in the STN will be studied by comparing two culture systems in which the STN is cultured either with or without the GP using long-term organotypic cultures. Third, the role of calcium channels in intrinsically bursting neurons in the generation of RSBA will be analyzed with whole cell path clamp and calcium imaging methods and the function of GABA receptor subunit compositions with the STN-GP circuitry in the generation of RSBA will be analyzed with immunocytochemistry, in situ hybridization histochemistry, and RT-PCR. Fourth, we will add to the Cx-Str-GP-STN organotypic culture a substantia nigra (SN) culture which provides for the main dopaminergic inputs to the striatum. We will analyze the changes in RSBA as a function of dopamine inputs by manipulating the system acutely and chronically using either dopamine receptor antagonists, or dopamine depletion by 6-hydroxydopamine (6-OHDA). Changes in RSBA will be correlated with changes in rebound burst activity of single cells and/or with changes in the expression of GABAa receptor subunits. This project will provide the basic neuronal frame work regarding the generation of rhythmically synchronized neuronal activity in the basal ganglia that has been related to motor dysfunction in PD.
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0.988 |