1985 — 1989 |
Boulant, Jack |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Functional Specificity of Neurons in Hypothalamic Tissue Slices |
0.915 |
1985 — 1988 |
Boulant, Jack A |
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. |
The Neural Control of Temperature Regulations
The preoptic area and anterior hypothalamus, PO/AH, are important structures in the regulation of body temperature. Certain PO/AH neurons not only sense changes in their own, central temperature; but in addition, they receive afferent synaptic information regarding peripheral and deep-body temperatures. This integrative neuronal network then communicates with other hypothalamic & brainstem areas to control a host of thermoregulatory responses; these responses include evaporative heat loss (sweating, panting), cutaneous blood flow, shivering (muscle tremor), metabolic endocrines, and various behaviors. Also, the neural control of these responses is dramatically affected by neural disease and lesions, fever-producing pyrogens, drugs, and thermal stress. Previous electrophysiological studies have revealed much about the various types of hypothalamic thermosensitive neurons and the ways in which afferent thermal information is integrated with hypothalamic thermal information. On the other hand, surprisingly little is known about the basis of neuronal thermosensitivity or about the synaptic connections within and between the different hypothalamic areas. To better understand this hypothalamic neuronal network, the proposed research will study its sensory and integrative properties using extracellular and intracellular recordings in both tissue slices and anesthetized animals. The thermosensitive properties of these neurons will be determined during synaptic blockade, thermal & electrical stimulation of synaptic pathways, and perfusion with endogenous factors, such as leukocytic pyrogen. The use of both frontal and horizontal tissue slices will permit a more precise characterization of the synaptic connections both within local neuronal networks as well as between different hypothalamic nuclei.
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1 |
1991 — 1993 |
Boulant, Jack A |
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. |
The Neural Control of Temperature Regulation
Certain rostral hypothalamic neurons sense their own temperature and receive afferent information about peripheral temperatures. This integrative neuronal network communicates with other hypothalamic and brain stem areas to control thermoregulatory responses, including cutaneous blood flow, evaporative heat loss (sweating, panting), shivering (muscle tremor), metabolic endocrines, and various behaviors. The neural control of these responses is dramatically affected by neural disease, lesions, drugs, and thermal stress. This network is also affected by fever-producing pyrogens, and during many disease states, it is important in evoking immune and acute phase responses. While previous studies reveal much about neuronal types and integration of thermal information, surprisingly little is known about the cellular basis of neuronal thermosensitivity. Using hypothalamic tissue slices, the immediate aim of this research is to understand inherent and synaptic mechanisms responsible for temperature sensitive and insensitive neurons. Our lone-term objective is to use this information to understand how endogenous substances (e.g., pyrogens) influence neurons regulating body temperature and other homeostatic systems. This is the first intracellular study of warm sensitive, cold sensitive. and temperature insensitive neurons in the mammalian hypothalamus. It tests hypotheses that inherent neuronal thermosensitivity is due to temperature dependent changes in membrane potential, pacemaker potential and excitability. To reveal mechanisms for these changes, input resistance will be studied and ionic conductances will be altered. Also, ouabain blockade of the Na-K pump will determine the pump's role in thermally-dependent changes in membrane characteristics, particularly in cold sensitive and temperature insensitive neurons. Finally, neurons showing delayed responses to temperature may be an important, but overlooked component of temperature regulation. Experiments will determine whether delayed thermal responses are due to synaptic mechanisms, the Na-K pump, or cyclic AMP.
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1 |
1992 — 2006 |
Boulant, Jack A |
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. |
Neural Control of Temperature Regulation
Certain rostral hypothalamic neurons sense their own temperature and receive afferent information about peripheral temperatures. This integrative neuronal network communicates with other hypothalamic and brain stem areas to control thermoregulatory responses, including cutaneous blood flow, evaporative heat loss (sweating, panting), shivering (muscle tremor), metabolic endocrines, and various behaviors. The neural control of these responses is dramatically affected by neural disease, lesions, drugs, and thermal stress. This network is also affected by fever-producing pyrogens, and during many disease states, it is important in evoking immune and acute phase responses. While previous studies reveal much about neuronal types and integration of thermal information, surprisingly little is known about the cellular basis of neuronal thermosensitivity. Using hypothalamic tissue slices, the immediate aim of this research is to understand inherent and synaptic mechanisms responsible for temperature sensitive and insensitive neurons. Our lone-term objective is to use this information to understand how endogenous substances (e.g., pyrogens) influence neurons regulating body temperature and other homeostatic systems. This is the first intracellular study of warm sensitive, cold sensitive. and temperature insensitive neurons in the mammalian hypothalamus. It tests hypotheses that inherent neuronal thermosensitivity is due to temperature dependent changes in membrane potential, pacemaker potential and excitability. To reveal mechanisms for these changes, input resistance will be studied and ionic conductances will be altered. Also, ouabain blockade of the Na-K pump will determine the pump's role in thermally-dependent changes in membrane characteristics, particularly in cold sensitive and temperature insensitive neurons. Finally, neurons showing delayed responses to temperature may be an important, but overlooked component of temperature regulation. Experiments will determine whether delayed thermal responses are due to synaptic mechanisms, the Na-K pump, or cyclic AMP.
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1 |